Tootfinder

Where Photons Have Been: Nowhere Without All Components of Their Wavefunctions
R. E. Kastner
https://arxiv.org/abs/2507.06362 https://

Where Photons Have Been: Nowhere Without All Components of Their Wavefunctions
A nested interferometer experiment by Danan et al (2013) is discussed and some ontological implications explored, primarily in the context of time-symmetric interpretations of quantum theory. It is pointed out that photons are supported by all components of their wavefunctions, not selectively truncated "first order" portions of them, and that figures representing both a gap in the photon's path and signals from the cut-off path are incorrect. It is also noted that the Transactional Formulation…

Cosmic filaments confirm unexplained cooling of CMB photons in two independent redshift ranges
Juan Ignacio Dom\'inguez Feldman, Luis A. Pereyra, Frode K. Hansen, Facundo Toscano, Diego Garcia Lambas
https://arxiv.org/abs/2506.08833

Cosmic filaments confirm unexplained cooling of CMB photons in two independent redshift ranges
Recent papers have reported an unexplained cooling of CMB photons passing through galaxies in nearby cosmic filaments $z<0.02$ at the $>5σ$ level. Here we show for the first time that this effect is also present at higher redshifts $0.02

Mid-IR hyperspectral imaging with undetected photons
Marlon Placke, Chiara Lindner, Felix Mann, Inna Kviatkovsky, Helen M. Chrzanowski, Hendrik Bartolomaeus, Frank K\"uhnemann, Sven Ramelow
https://arxiv.org/abs/2507.07861

Mid-IR hyperspectral imaging with undetected photons
Sensing with undetected photons has become a vibrant, application-driven research domain with a special focus on the mid-infrared (mid-IR) wavelength region. Since the mid-IR contains spectral bands with highly specific and strong molecular absorbance signatures, often referred to as fingerprints, a multitude of different samples and their compositions can be detected and quantified spectroscopically. Enhancing this inherently sample alteration-free spectroscopic method with imaging capabilitie…

Coherent superposition of emitted and resonantly scattered photons from a two-level system driven by an even-$\pi$ pulse
I. V. Krainov, A. I. Galimov, M. V. Rakhlin, A. A. Toropov, T. V. Shubina
https://arxiv.org/abs/2507.05943

Coherent superposition of emitted and resonantly scattered photons from a two-level system driven by an even-$π$ pulse
We report the observation of a bunching of ~3 photon states, which is a coherent superposition of emitted photons and resonantly scattered laser photons, arising upon excitation by even-$π$ pulses of a two-level system represented by a charged quantum dot in a microcavity. This phenomenon emerges because the exciting laser pulse contains several tens of photons whose quantum amplitude distribution creates such a superposition, and the polarization of the scattered photons is changed by the int…

Isospin symmetry breaking and gluon anomaly
A. A. Osipov
https://arxiv.org/abs/2509.07191 https://arxiv.org/pdf/2509.07191…

Isospin symmetry breaking and gluon anomaly
Isospin violating effects, both due to the nonvanishing quark mass difference $m_d-m_u$ and to virtual photons, are studied by fitting the squared masses of pseudoscalar mesons to the second order in the simultaneous expansion in powers of $1/N_c$, momenta and quark masses. It is shown that the gluon anomaly enhances the contribution of virtual photons and, thus, promotes to an additional (to the well-known current algebra result of Gross, Treiman and Wilczek) dynamical restoration of isospin s…

Mean free path of photons in relativistic heavy ion collisions
Jajati K. Nayak, Rupa Chatterjee
https://arxiv.org/abs/2508.05708 https://arxiv.org/pdf/2508…

Mean free path of photons in relativistic heavy ion collisions
Electromagnetic probes, such as photons and dileptons, play a key role in diagnosing the initial temperature of the hot and dense quark-gluon plasma (QGP) matter created in relativistic nuclear collisions at very high energies. This is due to their large mean free path $λ$, which allows them to escape the medium without significant interactions. Unlike hadronic particles, which experience multiple scatterings and are affected by the evolving medium, electromagnetic probes carry undistorted inf…

Violation of Bell Inequality with Unentangled Photons
Kai Wang, Zhaohua Hou, Kaiyi Qian, Leizhen Chen, Mario Krenn, Markus Aspelmeyer, Anton Zeilinger, Shining Zhu, Xiao-Song Ma
https://arxiv.org/abs/2507.07756

Violation of Bell Inequality with Unentangled Photons
Violation of local realism via Bell inequality - a profound and counterintuitive manifestation of quantum theory that conflicts with the prediction of local realism - is viewed to be intimately linked with quantum entanglement. Experimental demonstrations of such a phenomenon using quantum entangled states are among the landmark experiments of modern physics and paved the way for quantum technology. Here we report the violation of the Bell inequality that cannot be described by quantum entangle…

Latest results from the searches for ultra-high-energy photons at the Pierre Auger Observatory
Pierpaolo Savina (for the Pierre Auger Collaboration)
https://arxiv.org/abs/2509.05113

Latest results from the searches for ultra-high-energy photons at the Pierre Auger Observatory
The Pierre Auger Observatory is the largest air-shower detector in the world, offering unparalleled exposure to photons with energies above $5 \times 10^{16}$ eV. Since the start of data collection almost two decades ago, numerous searches for photons have been conducted using the detection systems of the Observatory. These searches have led to the most stringent upper limits on the diffuse photon flux. These limits place severe constraints on current models regarding the origin of ultra-high-e…

Canonical Electrodynamics in Ashtekar-Barbero variables
Federica Fragomeno, Saeed Rastgoo
https://arxiv.org/abs/2507.06276 https://ar…

Canonical Electrodynamics in Ashtekar-Barbero variables
We present the full Hamiltonian analysis of electrodynamics, including fermions, photons, and their interaction, on a general curved spacetime in Ashtekar-Barbero variables. No gauge fixing is performed and the theory is background independent. The details of the constraints of the theory for both Weyl and Dirac fermions are presented. Moreover, the equations of motion are derived and it is shown that they reduce to the equations of motion of the standard QFT in curved or flat spacetime in the …

Experiments to test the hypothesis for solar and dark matter axions
Babette D\"obrich, Igor G. Irastorza
https://arxiv.org/abs/2507.06414 https://

Experiments to test the hypothesis for solar and dark matter axions
We present a pedagogical introduction to the direct search of axions as dark matter, as well as to searches for solar axions. The plethora of experimental searches exploit the axion's coupling to two photons: They attempt to convert the axion dark matter to photons in a resonator placed in an external magnetic field or convert solar axions into X-rays in a magnet pointing towards the sun. We give a basic introduction to this concept, its many variants and to searches that exploit the axion's ot…

Evidence for a sign change of the ISW effect in the very recent universe: hot voids and cold overdensities at $z<0.03$
Frode K. Hansen, Diego Garcia Lambas, Andr\'es N. Ruiz, Facundo Toscano, Luis A. Pereyra
https://arxiv.org/abs/2506.08832

Evidence for a sign change of the ISW effect in the very recent universe: hot voids and cold overdensities at $z<0.03$
We find that CMB photons passing through local voids ($z<0.03$) are hotter than expected at the $2.7-3.6σ$ level. Combined with earlier findings showing a $>5σ$ cooling of CMB photons in galactic filaments in the same redshift range, we now have possible evidence for a negative Integrated Sachs-Wolfe (ISW) effect in the very recent universe. In addition to having opposite sign, the observed amplitude is an order of magnitude larger than the predicted Rees-Sciama and ISW effects for the nearby…

Tuning the probability detection of OAM entangled photons in Helical Ince-Gauss modes
A. A. Aguilar-Cardoso, D. Rodriguez-Guillen, R. Ramirez-Alarcon
https://arxiv.org/abs/2507.07035

Tuning the probability detection of OAM entangled photons in Helical Ince-Gauss modes
In this work we provide a detailed theoretical and experimental analysis of the two-photon Orbital Angular Momentum (OAM) entangled state, generated by a type-I Spontaneous Parametric Down Conversion (SPDC) process, when decomposed in terms of the Helical Ince-Gauss (HIG) modes basis. By exploiting the unique characteristics of this modal basis we show how the probability detection of the photon-pair can be tuned with the ellipticity parameter of the modes. We also show that, on the HIG basis t…

Stacked Hybrid RNN-CNN Reconstruction of X-ray Influence on 21-cm Brightness Temperature
S. Mobina Hosseini, Bahareh Soleimanpour Salmasi
https://arxiv.org/abs/2508.05842 https:…

Stacked Hybrid RNN-CNN Reconstruction of X-ray Influence on 21-cm Brightness Temperature
The X-ray photons substantially affect the thermal and ionization states of the intergalactic medium (IGM) during the Epoch of Reionization (EoR), thereby significantly influencing the 21-cm line observables such as its sky-averaged (global) brightness temperature. Nevertheless, the complicated dependency of astrophysical processes on a broad spectrum of parameters, including X-ray efficiency, spectral characteristics, and gas dynamics, makes precisely simulating the effect of X-ray flux challe…

Impact of Polarization Distinguishability on Coherence in QIUP
Gaytri Arya, Paolo Bianchini, Alberto Diaspro
https://arxiv.org/abs/2507.06879 https://

Impact of Polarization Distinguishability on Coherence in QIUP
Quantum imaging with undetected photons (QIUP) is a promising technique for non-invasive imaging, particularly at wavelengths where detectors are inefficient or unavailable. Recent studies have investigated the role of polarization in QIUP schemes. In this work, we examine whether post-generation optical elements can recover interference when the signal photons are distinguishable in polarization at the source. Specifically, we employ a Mach-Zehnder interferometer after the photon pairs are gen…

Arago, which is developing a photonic chip, codenamed JEF, that is designed to cut AI energy use by ten times at a comparable cost, raised a $26M seed (Tamara Djurickovic/Tech.eu)
https://tech.eu/2025/07/08/arago-raises-2…

Arago raises $26M to slash AI energy consumption with breakthrough photonic chip
Arago, a deeptech startup pioneering a new class of energy-efficient AI chips powered by light, has raised $26 million in seed funding to accelerate the commercialisation of its photonic processor, codenamed “JEF”. At the core of “JEF” is a proprietary photonic technology that processes data using lasers instead of transistors. By using photons, light particles that generate much less heat than electrons, this chip can deliver the same performance as top GPUs while consuming 10× less …

Dark states of electrons in a quantum system with two pairs of sublattices
Yoonah Chung, Minsu Kim, Yeryn Kim, Seyeong Cha, Joon Woo Park, Jeehong Park, Yeonjin Yi, Dongjoon Song, Jung Hyun Ryu, Kimoon Lee, Timur K. Kim, Cephise Cacho, Jonathan Denlinger, Chris Jozwiak, Eli Rotenberg, Aaron Bostwick, Keun Su Kim
https://arxiv.or…

Dark states of electrons in a quantum system with two pairs of sublattices
A quantum state of matter that is forbidden to interact with photons and is therefore undetectable by spectroscopic means is called a dark state. This basic concept can be applied to condensed matter where it suggests that a whole band of quantum states could be undetectable across a full Brillouin zone. Here we report the discovery of such condensed matter dark states in palladium diselenide as a model system that has two pairs of sublattices in the primitive cell. By using angle-resolved phot…

Cavity-induced Eliashberg effect: superconductivity vs charge density wave
Md Mursalin Islam, Michele Pini, R. Flores-Calder\'on, Francesco Piazza
https://arxiv.org/abs/2509.07865

Cavity-induced Eliashberg effect: superconductivity vs charge density wave
Recent experiments have shown that non-equilibrium effects can play a key role in cavity-based control of material phases, notably in systems with charge-density-wave order. Motivated by this, we extend the theory of the Eliashberg effect, originally developed for superconducting phases, to charge-density-wave phases. Starting from a minimal electronic model where superconductivity and charge-density-wave order are equivalent at equilibrium, we introduce coupling to cavity photons, which are in…

Gravitational Photon Polarization Twist to Probe the Early Universe and the Galactic Center
Rodolfo Capdevilla
https://arxiv.org/abs/2507.05347 https://

Gravitational Photon Polarization Twist to Probe the Early Universe and the Galactic Center
It is known that gravitational wave backgrounds (GWBs) change the polarization state of photons. This letter explores the possibility of using this effect to detect GWBs. The proposed experiment features a vertically polarized laser pulse traveling through a GWB before reaching a birefringent material which separates photons by polarization. Photons that emerge the birefringent material horizontally polarized are counted as signal photons. A space-based setup of a million km (comparable to the …

State of the Ice Model in the IceCube Observatory
Dmitry Chirkin (for the IceCube Collaboration), Martin Rongen (for the IceCube Collaboration)
https://arxiv.org/abs/2507.06341

State of the Ice Model in the IceCube Observatory
IceCube is a neutrino observatory located at the South Pole that uses Antarctic ice as a medium for detection of Cherenkov photons. As such, analysis of the data relies on our understanding of the properties of ice within and around the instrumented volume. Over the years we have made significant progress in understanding the glacial ice and now have a comprehensive model that covers many of the relevant aspects of the photon propagation in it. In this report we give a historical overview of th…

Towards integrated sensors for optimized OCT with undetected photons
Franz Roeder, Ren\'e Pollmann, Viktor Quiring, Christof Eigner, Benjamin Brecht, Christine Silberhorn
https://arxiv.org/abs/2508.05320

Towards integrated sensors for optimized OCT with undetected photons
The development of practical sensors for optical coherence tomography (OCT) with undetected photons requires miniaturization via integration. To be practical, these sensors must exhibit a large spectral bandwidth and a high brightness, which are linked to a high axial resolution and a sufficient signal to noise ratio, respectively. Here, we combine these requirements in a scheme for OCT-measurements with undetected photons based on nonlinear Ti:LiNbO$_3$ waveguides. We investigate the performan…

Theory of circular dichroism in resonant inelastic x-ray scattering
M. Furo, A. Hariki, J. Kune\v{s}
https://arxiv.org/abs/2508.04388 https://arxiv.org/pdf…

Theory of circular dichroism in resonant inelastic x-ray scattering
We analyze circular dichroism (CD) in resonant inelastic x-ray scattering (RIXS) in magnetic materials. We define RIXS-CD as the difference between scattering amplitudes for the right- and left-circularly polarized incoming photons and unpolarized (total) outgoing photons. We employ the impurity approximation, in which the interference between scattering events on different atoms is neglected. We perform the symmetry analysis of several common antiferromagnetic and altermagnetic structures and …

First searches for axion and dark photon dark matter with MADMAX
Fabrice Hubaut (on behalf of the MADMAX Collaboration)
https://arxiv.org/abs/2509.06398 https://

First searches for axion and dark photon dark matter with MADMAX
The MAgnetized Disk and Mirror Axion eXperiment (MADMAX) is a future experiment aiming to detect dark matter axions from the galactic halo by resonant conversion to photons in a strong magnetic field. It uses a novel concept based on a stack of dielectric disks in front of a mirror, called booster, to enhance the potential signal from axion-photon conversion over a significant mass range. In its final version, MADMAX aims to scan the uncharted QCD axion mass range around 100 $μ$eV, favored by …

Black hole accretion, star formation, and chemical evolution with PRIMA/FIRESS spectroscopy: toward the cosmic noon and beyond
Juan Antonio Fern\'andez-Ontiveros, Luigi Spinoglio, Tohru Nagao
https://arxiv.org/abs/2509.06954

Black hole accretion, star formation, and chemical evolution with PRIMA/FIRESS spectroscopy: toward the cosmic noon and beyond
The PRobe far-Infrared Mission for Astrophysics (PRIMA) will deliver the first comprehensive view of the obscured side of star formation and black hole accretion that dominates galaxy growth at cosmic noon. Around 90% of UV/optical photons from young stars and Active Galactic Nuclei (AGN) are absorbed by dust and reradiated in the mid- to far-infrared, where key diagnostic lines trace accretion, star formation, and the physical and chemical conditions of galaxies. PRIMA will conduct blind spect…

Spin Systems Coupled to Photons: A Case study of Phase Transition in a One-Dimensional Classical Ferromagnetic Ising Spin Chain at Finite Temperature
Shuntaro Otake, Motoaki Bamba
https://arxiv.org/abs/2507.01486

Spin Systems Coupled to Photons: A Case study of Phase Transition in a One-Dimensional Classical Ferromagnetic Ising Spin Chain at Finite Temperature
Although one-dimensional classical spin chains do not exhibit phase transitions, we found that a phase transition does occur when they are coupled to a cavity photon mode. This provides one of the simplest examples demonstrating that finite-temperature superradiant phase transitions can emerge from long-range fully connected interactions mediated by photons and interactions within the material.

Studying magnetic circular vortex dichroism effect for photoionization of Rydberg atoms with vortex photons
Pengcheng Zhao
https://arxiv.org/abs/2509.06603 https://

Constraints on primordial black holes from interstellar dust temperature in the Galaxy
A. N. Melikhov (P.N. Lebedev Physical Institute, Moscow, Russia), E. V. Mikheeva (Astro Space Center of the P.N. Lebedev Physical Institute, Moscow, Russia)
https://arxiv.org/abs/2506.08605

Constraints on primordial black holes from interstellar dust temperature in the Galaxy
The photons emitted by primordial black holes (PBHs) can be a heating factor for interstellar dust. Assuming that dust in the Galaxy has a homogeneous distribution and that PBHs have the same distribution as dark matter (DM), we constrain the fraction of PBHs in DM from the observational dust temperature in the Galaxy.

Controlling quantum entanglement with classical non-separable light
R. F. Barros, A. L. S. Santos Junior, A. Z. Khoury, R. Fickler
https://arxiv.org/abs/2507.06462

Controlling quantum entanglement with classical non-separable light
Here we investigate the quantum frequency conversion of entangled photons driven by a classically non-separable laser beam. We show that the frequency conversion dynamics is described by a quantum channel that stems from the classical drive field through the channel-state duality - the quantum channel is dual to the classical coherence matrix of the drive field. This implies that the evolution of entanglement in the conversion process is bound by the classical non-separability of the drive fiel…

Probing lepton flavor violating dark matter scenarios via astrophysical photons and positrons
Jin-Han Liang, Yi Liao, Xiao-Dong Ma
https://arxiv.org/abs/2508.05121 https://

Probing lepton flavor violating dark matter scenarios via astrophysical photons and positrons
In this Letter we explore, for the first time, the constraints on lepton flavor violating (LFV) dark matter (DM) scenarios via the astrophysical photons and positrons, including both the annihilation and decay modes, ${\tt DM(+DM)}\to e^\pm μ^\mp, e^\pm τ^\mp, μ^\pm τ^\mp$. Given the presence of LFV interactions in various DM models and the challenge of probing such interactions at terrestrial facilities, such as DM direct detection and collider experiments, indirect detection offers a uniq…

Dirac particles, spin and photons
Alexander D. Popov
https://arxiv.org/abs/2508.21590 https://arxiv.org/pdf/2508.21590

Dirac particles, spin and photons
We describe relativistic particles with spin as points moving in phase space $X=T^* R^{1,3}\times C^2_L\times C^2_R$, where $T^* R^{1,3}=R^{1,3}\times R^{1,3}$ is the space of coordinates and momenta, and $C^2_L$ and $C^2_R$ are the spaces of representation of the Lorentz group of type $(\frac12 , 0)$ and $(0, \frac12)$. Passing from relativistic mechanics with a Lorentz-invariant Hamiltonian function $H$ on the phase space $X$ to quantum mechanics with a Hamiltonian operator $\hat H$, we intro…

Probing Strong-Field QED via Angle-Discriminated Emissions from Electrons Traversing Colliding Laser Pulses
C. Olofsson, A. Gonoskov
https://arxiv.org/abs/2506.08741

Probing Strong-Field QED via Angle-Discriminated Emissions from Electrons Traversing Colliding Laser Pulses
Future laser-electron colliders will reach quantum parameters $χ$ well in excess of unity, enabling studies of strong-field QED in extreme regimes. However, statistical inference in such experiments requires mitigating premature radiative losses of electrons to enable high-$χ$ QED events, as well as separating the detectable signal of these events from that of lower-$χ$ particles and photons produced by QED cascades. We propose a collider geometry in which electrons traverse the waist of two…

Replaced article(s) found for gr-qc. https://arxiv.org/list/gr-qc/new
[2/2]:
- Generalised Aichelburg-Sexl and Self-Force for photons
Abedennour Dib, Aymeric Garnier, Alessandro Spallicci

Detecting entanglement between quantum emitters using directional emission
Ivan Saychenko, Robert Weiss, Rita Veilande, Scott Parkins, Mark Sadgrove, Sandro Wimberger
https://arxiv.org/abs/2508.06210

Detecting entanglement between quantum emitters using directional emission
Recently, it was shown that quantum interference in a system containing a polarized and unpolarized emitter can allow directional emission of photons into a circulating cavity. Here, we ask whether high directionality of photon emission in this system implies a high degree of quantum correlation between the two emitters. We show that the answer is a qualified "yes", with photon emission directionality and emitter-emitter entanglement showing a monotonic relationship over a broad parameter range…

Constraints on Axion-Like Particles from 16.5 Years of Fermi-LAT Data and Prospects for VLAST
Zhi-Qi Guo, Yue-Lin Sming Tsai, Lei Wu, Zi-Qing Xia
https://arxiv.org/abs/2507.07786 …

Constraints on Axion-Like Particles from 16.5 Years of Fermi-LAT Data and Prospects for VLAST
Axion-like particles (ALPs), hypothetical particles beyond the Standard Model, are considered as promising dark matter candidates. ALPs can convert into photons and vice versa in a magnetic field via the Primakoff effect, potentially generating detectable oscillation in $γ$-ray spectra. This study analyzes 16.5 years of data from the Fermi Large Area Telescope (Fermi-LAT) on NGC 1275, the brightest galaxy in the Perseus cluster, to constrain the ALP parameter space. Our results improve the pre…

Asymmetric two-photon response of an incoherently driven quantum emitter
Lennart Jehle, Lena M. Hansen, Patrik I. Sund, Thomas W. Sand{\o}, Raphael Joos, Michael Jetter, Simone L. Portalupi, Mathieu Bozzio, Peter Michler, Philip Walther
https://arxiv.org/abs/2507.07082

Asymmetric two-photon response of an incoherently driven quantum emitter
Quantum emitters promise to emit exactly one photon with high probability when pumped by a laser pulse. However, even in ideal systems, re-excitation during a laser pulse causes the consecutive emission of two photons, thus limiting the single-photon purity. Although the probability and properties of re-excitation are largely determined by the optical excitation method, until now only resonant driving has been studied. Here, we demonstrate qualitative differences in the process arising from pho…

A spin-embedded diamond optomechanical resonator with mechanical quality factor exceeding one million
Hyunseok Oh, Viraj Dharod, Carl Padgett, Lillian B. Hughes, Jayameenakshi Venkatraman, Shreyas Parthasarathy, Ekaterina Osipova, Ian Hedgepeth, Jeffrey V. Cady, Luca Basso, Yongqiang Wang, Michael Titze, Edward S. Bielejec, Andrew M. Mounce, Dirk Bouwmeester, Ania C. Bleszynski Jayich

A spin-embedded diamond optomechanical resonator with mechanical quality factor exceeding one million
Diamond optomechanical crystal (OMC) devices with embedded color center spins are promising platforms for a broad range of applications in quantum sensing, networking, and computing applications, offering an interface between a GHz-frequency mechanical mode and both optical photons and coherent spins. A crucial but elusive step towards realizing this platform is to engineer a device with a high-quality factor mechanical mode while preserving the bulk-like coherence of embedded spins. Here we de…

Resonant axion and dark photon production in magnetic white dwarfs
Nirmalya Brahma, Ella Iles, Hugo Sch\'erer, Katelin Schutz
https://arxiv.org/abs/2509.07085 https://

Resonant axion and dark photon production in magnetic white dwarfs
Using magnetic white dwarfs as a case study, we show that the emission of sub-MeV bosons from stellar plasmas can be substantially modified in the presence of a magnetic field. In particular, the magnetic field-induced anisotropy and cyclotron resonance both significantly affect the in-medium dispersion relations of the Standard Model photon. As a result, resonant level crossing between photons and other light bosons occurs under environmental conditions that differ from the resonance criteria …

Gamma-ray lines, electron-positron annihilation, and possible radio emission in X-ray pulsars
Alexander A. Mushtukov, Emir Tataroglu, Alex J. Cooper, Sergey S. Tsygankov
https://arxiv.org/abs/2509.05427

Gamma-ray lines, electron-positron annihilation, and possible radio emission in X-ray pulsars
Accretion onto neutron stars (NSs) in X-ray pulsars (XRPs) results in intense X-ray emission, and under specific conditions, high-energy nuclear interactions that produce gamma-ray photons at discrete energies. These interactions are enabled by the high free-fall velocities of accreting nuclei near the NS surface and give rise to characteristic gamma-ray lines, notably at 2.2 MeV, 5.5 MeV, and 67.5 MeV. We investigate the production mechanisms of these lines and estimate the resulting gamma-ray…

High brightness multi-MeV photon source driven by a petawatt-scale laser wakefield accelerator
E. Gerstmayr, B. Kettle, M. J. V. Streeter, L. Tudor, O. J. Finlay, L. E. Bradley, R. Fitzgarrald, T. Foster, P. Gellersen, A. E. Gunn, O. Lawrence, P. P. Rajeev, B. K. Russell, D. R. Symes, C. D. Murphy, A. G. R. Thomas, C. P. Ridgers, G. Sarri, S. P. D. Mangles

High brightness multi-MeV photon source driven by a petawatt-scale laser wakefield accelerator
We present an experimental demonstration of a bright multi-MeV gamma source driven by a petawatt laser. The source generates on average $(1.2\pm0.6)\times10^9$ photons above 1 MeV per pulse, exceeding those of previous all-optical sources by a hundred times, and reached a peak spectral brightness of $(3.9 \pm 1.5)\times 10^{22}$ photons/mm$^2$/mrad$^2$/s/0.1%BW at $ε_γ\approx11$ MeV. The source was produced by inverse Compton scattering of a laser wakefield accelerated GeV electron beam and i…

Cavity-QED-controlled two-dimensional Moir\'e Excitons without twisting
Francesco Troisi, Hannes H\"ubener, Angel Rubio, Simone Latini
https://arxiv.org/abs/2508.02388 …

Cavity-QED-controlled two-dimensional Moiré Excitons without twisting
We propose an all-optical Moiré-like exciton confinement by means of spatially periodic optical cavities. Such periodic photonic structures can control the material properties by coupling the matter excitations to the confined photons and their quantum fluctuations. We develop a low energy non-perturbative quantum electro-dynamical description of strongly coupled excitons and photons at finite momentum transfer. We find that in the classical limit of a laser driven cavity the induced optical c…

Aspheric lens design proposal for near-perfect mode-matching of a broadband quantum dot micropillar to a single-mode fibre
Yichen Zhang, David Dlaka, James McDougall, James Y Tai, Petros Androvitsaneas, Edmund Harbord, Ruth Oulton, Andrew B. Young
https://arxiv.org/abs/2508.06223

Aspheric lens design proposal for near-perfect mode-matching of a broadband quantum dot micropillar to a single-mode fibre
Quantum dots in micropillars are one of the most promising options for a bright, deterministic single photon source. While highly efficient devices (>95%) have been designed, there remains a significant bottleneck that impacts the overall system efficiency: the large numerical aperture of the output mode. This leads to inefficient coupling of emitted photons into single-mode fibre, thus limiting practical integration into quantum computing and communication architectures. We show that with the …

General finite two-loop amplitude integrand for photoproduction in quark annihilation
Charalampos Anastasiou, Julia Karlen, Roshni Sahoo, George Sterman, Matilde Vicini
https://arxiv.org/abs/2509.07805

General finite two-loop amplitude integrand for photoproduction in quark annihilation
The construction of integrands free of infrared and ultraviolet singularities may enable the application of numerical methods to evaluate loop amplitudes that are inaccessible with analytic techniques. At two loops, finite amplitude integrands have been constructed for the production of off-shell or massive colorless particles via quark annihilation. In this article, we extend this class of processes to include real photons in the final state. To achieve this, we introduce appropriate momentu…

Generalised Aichelburg-Sexl and Self-Force for photons
Abedennour Dib, Aymeric Garnier, Alessandro Spallicci
https://arxiv.org/abs/2507.00767 https://

Generalised Aichelburg-Sexl and Self-Force for photons
We generalise the Aichelburg-Sexl Stress-Energy-Momentum tensor for massless particles to include motion with angular velocity, introducing tensorial spherical harmonics. Further, we make steps towards the concept of self-force for photons which could manifest as frequency shift.

Long-term neutrino emission from a core-collapse supernova with axion-photon coupling
Masamitsu Mori, Kanji Mori
https://arxiv.org/abs/2509.05973 https://a…

Long-term neutrino emission from a core-collapse supernova with axion-photon coupling
We perform long-term general-relativistic neutrino-radiation hydrodynamic simulations for core-collapse supernovae (CCSNe) which include the cooling effect induced by the coupling between axion-like particles (ALPs) and photons. We take into account the \kanji{photon} coalescence and the Primakoff effect, and investigate ALPs with the mass of 10\,MeV and the coupling constant $g_{aγ}$ of $1.0\times10^{-9}{\rm \,GeV^{-1}}$ to $7.0\times10^{-9}{\rm \,GeV^{-1}}$. It is found that the effects of t…

Thin-film Al0.30Ga0.70As (111) as a flat source of high-purity orthogonally polarized entangled photons
Simon Stich, Vitaliy Sultanov, Trevor Blakie, Qingyu Shi, Zbig Wasiliewski, Mikhail A. Belkin, Maria Chekhova
https://arxiv.org/abs/2509.03978

Thin-film Al0.30Ga0.70As (111) as a flat source of high-purity orthogonally polarized entangled photons
Flat-optics platforms offer new opportunities for the generation of entangled photons by relaxing traditional phase-matching constraints, enabling the use of a broader range of nonlinear materials. Among these, gallium arsenide and aluminum gallium arsenide stand out for their exceptionally high second-order nonlinearities, but their conventional orientation (001) has limited their applicability for photon-pair generation. By transitioning to crystals with (111) surface orientation, we overcome…

Breaking Through the Cosmic Fog: JWST/NIRSpec Constraints on Ionizing Photon Escape in Reionization-Era Galaxies
Emma Giovinazzo, Pascal A. Oesch, Andrea Weibel, Romain A. Meyer, Callum Witten, Aniket Bhagwat, Gabriel Brammer, John Chisholm, Anna de Graaff, Rashmi Gottumukkala, Michelle Jecmen, Harley Katz, Joel Leja, Rui Marques-Chaves, Michael Maseda, Irene Shivaei, Maxime Trebitsch, Anne Verhamme

Breaking Through the Cosmic Fog: JWST/NIRSpec Constraints on Ionizing Photon Escape in Reionization-Era Galaxies
The escape fraction of Lyman continuum photons (fesc(LyC)) is the last key unknown in our understanding of cosmic reionization. Directly estimating the escape fraction (fesc) of ionizing photons in the epoch of reionization (EoR) is impossible, due to the opacity of the intergalactic medium (IGM). However, a high fesc leaves clear imprints in the spectrum of a galaxy, due to reduced nebular line and continuum emission, which also leads to bluer UV continuum slopes (betaUV). Here, we exploit the…

Low-energy multi-photon scattering at tree-level and one-loop order in a homogeneous electromagnetic field
Ivan Ahumada, Patrick Copinger, James P. Edwards
https://arxiv.org/abs/2507.22308

Low-energy multi-photon scattering at tree-level and one-loop order in a homogeneous electromagnetic field
We study low energy photons coupled to scalar and spinor matter in the presence of an arbitrary homogeneous electromagnetic field in a first-quantised (worldline) approach. Utilising a Fock-Schwinger gauge for both the scattering photons and homogeneous background, simple compact expressions are found for both the photon- and background-dressed effective action and propagator in scalar and spinor quantum electrodynamics. The low-energy limit allows identification of the coupling of the scatteri…

Axion-like Particles and their Possible Impact on the Very High-Energy Spectrum of M87 Observed by LHAASO
A. Pratts, D Avila Rojas, J. Serna-Franco, M. M. Gonz\'alez, R. Alfaro
https://arxiv.org/abs/2507.05637

Axion-like Particles and their Possible Impact on the Very High-Energy Spectrum of M87 Observed by LHAASO
The detection of very high-energy (VHE) gamma rays from the active galaxy M87 by LHAASO, showing a possible spectral hardening around $20$ TeV, motivates the search for new physics beyond standard emission models. One promising candidate is axion-like particles (ALPs), hypothetical pseudo-scalar bosons that can oscillate into photons in the presence of cosmic magnetic fields. In this work, we investigate whether photon-ALP oscillations and an additional ALP-induced component can account for the…

Dark photon dark matter constraints and a tentative signal at the TASEH experiment
Yuan-Hann Chang, Cheng-Wei Chiang, Hien Thi Doan, Nick Houston, Jinmian Li, Tianjun Li, Lina Wu, Xin Zhang
https://arxiv.org/abs/2507.00784

Dark photon dark matter constraints and a tentative signal at the TASEH experiment
The dark photon is a well motivated candidate for the dark matter which comprises most of the mass of our visible Universe, leading to worldwide experimental and observational efforts towards its discovery. A primary tool in this search is the cavity haloscope, which facilitates resonantly enhanced conversion to photons from both dark photons and axions. In this context, limits from axion search experiments are often directly converted into dark photon constraints, without re-analyzing the orig…

Interplay of prompt and non-prompt photons in photon-triggered jet observables
Chathuranga Sirimanna (JETSCAPE Collaboration), Yasuki Tachibana (JETSCAPE Collaboration), Abhijit Majumder (JETSCAPE Collaboration), Aaron Angerami (JETSCAPE Collaboration), Ritu Arora (JETSCAPE Collaboration), Steffen Bass (JETSCAPE Collaboration), Yi Chen (JETSCAPE Collaboration), Ritoban Datta (JETSCAPE Collaboration), Lipei Du (JETSCAPE Collaboration), Raymond Ehlers (JETSCAPE Collaboration), Hannah Elf…

Interplay of prompt and non-prompt photons in photon-triggered jet observables
Prompt photons are important yet challenging to observe in relativistic heavy-ion collisions, as they are produced in the early stages and traverse almost the entire QGP medium without interaction. Experimental analyses typically employ isolation cuts, in the hope to identify prompt photons. Most theoretical studies consider only events with actual prompt photons, assuming no contribution from isolated non-prompt photons to reduce computational cost. For the first time, we present a study that …

Tight-binding photonics
Jing Li, Aodong Li, Yutao Chen, Tao Xiao, Renwen Huang, Xiaolu Zhuo, Jun Guan, Zhen Gao, Peng Zhan, Minghui Lu, Biye Xie
https://arxiv.org/abs/2508.04465

Tight-binding photonics
Photonics, dealing with the generation, manipulation, and detection of photons in various systems, lays the foundation of many advanced technologies. A key task of photonics is to know how photons propagate in complex media such as periodic and aperiodic photonic crystals. The conventional wisdom is to numerically solve the Maxwell equations either by dedicated numerical techniques or brute-force finite-element calculations. Recently, the strict analogy between photonic crystals and theoretical…

Ultrafast dynamics of quantum matter driven by time-energy entangled photons
Giovanni Citeroni, Marco Polini, Michael Dapolito, D. N. Basov, Giacomo Mazza
https://arxiv.org/abs/2506.12211

Ultrafast dynamics of quantum matter driven by time-energy entangled photons
We study the dynamics of quantum matter interacting with time-energy entangled photons. We consider the stimulation of a collective mode of a two-dimensional material by means of one of the two partners of a time-energy entangled pair of photons. Using an exactly solvable model, we analyze the out-of-equilibrium properties of both light and matter degrees of freedom, and show how entanglement in the incident photons deeply modifies relevant time scales of the light-matter interaction process. W…

Advanced techniques of searching for flares of ultra-high-energy photons from point sources
Jaroslaw Stasielak, Chaitanya Priyadarshi, Dariusz G\'ora, Nataliia Borodai, Marcus Niechciol, Jan P\k{e}kala
https://arxiv.org/abs/2507.02777

Advanced techniques of searching for flares of ultra-high-energy photons from point sources
Astrophysical flares are one of the possible prominent source classes of ultra-high-energy (UHE, $E > 10^{17}$ eV) cosmic rays, which can be detected by recording clusters of extensive air showers in arrays of detectors. The search for sources of neutral particles offers distinct advantages over searching for sources of charged particles, as the former traverse cosmic distances undeflected by magnetic fields. While no cosmic-ray photons exceeding $10^{17}$ eV have been definitively detected, id…

The AstroSat UV Deep Field South-V: Constraints on the average escape of ionizing photons in the cosmic dusk
Soumil Maulick, Kanak Saha
https://arxiv.org/abs/2508.20011 https://…

The AstroSat UV Deep Field South-V: Constraints on the average escape of ionizing photons in the cosmic dusk
We investigate the escape of ionizing (Lyman-continuum; LyC) photons from 49 star-forming galaxies at redshifts $\sim 1-1.5$, using far-ultraviolet (FUV) imaging from the Ultra-Violet Imaging Telescope (UVIT) onboard AstroSat. The sample spans a wide range of stellar masses and UV luminosities. LyC emission is undetected in most galaxies (42/49), and stacking these galaxies yields only an upper limit on the observed LyC-to-nonionizing UV flux density ratio ($({F}_{λ,\rm{LyC}}/{F}_{λ,\rm{UV}})…

Theory Framework of Multiplexed Photon-Number-Resolving Detectors
Xiaobin Zhao, Hezheng Qin, Hong X. Tang, Linran Fan, Quntao Zhuang
https://arxiv.org/abs/2507.05554

Theory Framework of Multiplexed Photon-Number-Resolving Detectors
Photon counting is a fundamental component in quantum optics and quantum information. However, implementing ideal photon-number-resolving (PNR) detectors remains experimentally challenging. Multiplexed PNR detection offers a scalable and practical alternative by distributing photons across multiple modes and detecting their presence using simple ON-OFF detectors, thereby enabling approximate photon-number resolution. In this work, we establish a theoretical model for such detectors and prove th…

Low-coherence interferometry with undetected mid-infrared photons in the high-gain regime
Giovanni Zotti, Dmitri B. Horoshko, Mikhail I. Kolobov, Yoad Michael, Ziv Gefen, Maria V. Chekhova, Kazuki Hashimoto
https://arxiv.org/abs/2509.03349

Low-coherence interferometry with undetected mid-infrared photons in the high-gain regime
We develop a high-parametric-gain SU(1,1) interferometer based on an aperiodically poled Potassium Titanyl Phosphate (apKTP) crystal, enabling frequency-domain low-coherence interferometry with undetected mid-infrared photons. The system achieves a signal-to-noise ratio as high as 40 dB and axial resolution of 30 $μ$m, with a 3 $μ$m-centered idler beam. By increasing the poling-period range, we also improve the axial resolution to 17 $μ$m, demonstrating a straightforward route to enhance the…

There is no ultrastrong coupling with photons
Diego Fern\'andez de la Pradilla, Esteban Moreno, Johannes Feist
https://arxiv.org/abs/2508.00702 https://

There is no ultrastrong coupling with photons
Theoretical accounts of ultrastrongly coupled light-matter systems commonly assume that it arises from the interaction of an emitter with propagating photon modes supported by a structure, understanding photons as the excitations of the transverse electromagnetic field. This description discards the Coulomb interaction between the emitter and structure charges. Here, we show with a general argument based on electromagnetic constraints that the emitter-photon coupling strength is fundamentally l…

A dump leakage calorimeter to measure the flux of high-energy electrons and photons
Antonios Athanassiadis, Ties Behnke, Jonas Bj\"orklund Svensson, Oleksandr Borysov, Maryna Borysova, Lewis Boulton, Sarawit Chindaratchakul, Beate Heinemann, Louis Helary, Ruth Jacobs, Advait Kanekar, Jenny List, Tianyun Long, Tanguy Marsault, Felipe Pe\~na, Stefan Schmitt, Sarah Schr\"oder, Ivo Schulthess, Stephan Wesch, Matthew Wing, Jonathan Wood

A dump leakage calorimeter to measure the flux of high-energy electrons and photons
We developed a novel apparatus based on a lead glass calorimeter that can measure the flux of high-energy electrons or photons. Our detector uses the electromagnetic shower leakage from the beam dump, where the particles are disposed of at the beamline's end. A prototype of such a calorimeter was set up at the FLASHForward experiment at DESY. We show that it can measure the electron bunch charge with precision and accuracy at the 10% and 3% level, respectively. Additionally, it is capable of de…

Controllable Non-reciprocity in Multi-sphere Loaded Chiral Resonator
Maxime Ardisson, Guillaume Bourcin, Julien Haumant, Romain Lebrun, Isabella Boventer, Vincent Castel
https://arxiv.org/abs/2506.22230

Controllable Non-reciprocity in Multi-sphere Loaded Chiral Resonator
Cavity magnonics explores the hybridization of photons and magnons within microwave resonators. One of the hallmarks of these systems is their ability to exhibit non-reciprocity, which is a key feature for radio frequency (RF) applications. One way to control non-reciprocal behaviors in cavity magnonics is the design of chiral cavities that allow selective coupling between photons and magnons depending on their polarization. However, a built-in chiral platform to harness and control non-recipro…

A new constraint on the $y$-distortion with FIRAS: robustness of component separation methods
Alina Sabyr, Giulio Fabbian, J. Colin Hill, Federico Bianchini
https://arxiv.org/abs/2508.04593

A new constraint on the $y$-distortion with FIRAS: robustness of component separation methods
The sky-averaged Compton-$y$ distortion in the cosmic microwave background (CMB) energy spectrum, $\langle y \rangle$, provides information about energy injection in the Universe occurring at $z \lesssim 5\times10^{4}$. It is primarily sourced by the thermal Sunyaev-Zeldovich effect -- the up-scattering of CMB photons on free electrons in collapsed dark matter halos. In this work and our companion paper, Ref. [1], we perform a re-analysis of the archival COBE/FIRAS data to constrain $\langle y …

Cavity quantum electrodynamics on a nanocapillay fiber using a composite photonic crystal symmetric cavity
Srinu Gadde, Jelba John, Elaganuru Bashaiah, Ramachandrarao Yalla
https://arxiv.org/abs/2507.05804

Cavity quantum electrodynamics on a nanocapillay fiber using a composite photonic crystal symmetric cavity
We report the cavity quantum electrodynamics conditions using a composite photonic crystal symmetric cavity (CPCSC) on an optical nanocapillary fiber (NCF). The CPCSC is formed by combining the NCF and the symmetric defect mode nano-grating. The maximum channeling efficiency up to 87% is realized by placing the single quantum emitter at the anti-node position of the CPCSC. The current platform paves the way for manipulating single photons with applications in quantum technology.

The impact of kilonova seed photons on GRB VHE emission
John P. Hope, Hendrik J. van Eerten
https://arxiv.org/abs/2507.21233 https://arxiv.org/pdf/2507.212…

The impact of kilonova seed photons on GRB VHE emission
Over the last few years, an increasing number of gamma-ray bursts (GRB) have been detected with very high energy (VHE) emission in excess of 100 GeV, with a few cases above 1 TeV. In several instances, synchrotron seed photons do not fully explain the emission observed, suggesting the presence of other seed photon sources to up-scatter. In this work, we consider the kilonova as a source of seed photons for up-scattering in the afterglow. We model the kilonova as a thermal source injecting into …

Microscopic approach to the quantized light-matter interaction in semiconductor nanostructures: Complex coupled dynamics of excitons, biexcitons, and photons
Hendrik Rose, Stefan Schumacher, Torsten Meier
https://arxiv.org/abs/2506.22220

Microscopic approach to the quantized light-matter interaction in semiconductor nanostructures: Complex coupled dynamics of excitons, biexcitons, and photons
We present a microscopic and fully quantized model to investigate the interaction between semiconductor nanostructures and quantum light fields including the many-body Coloumb interaction between photoexcited electrons and holes. Our approach describes the coupled dynamics of the quantum light field and single and double electron-hole pairs, i.e., excitons and biexcitons, and exactly accounts for Coulomb many-body correlations and carrier band dispersions. Using a simplified yet exact approach,…

Enhancing Photon Indistinguishability of Spectrally Mismatched Single Photons by Cavity Floquet Engineering
J. W. Yu, X. Q. Zhou, Z. B. Ni, X. T. Cheng, Y. Zhao, H. H. Zhu, C. H. Li, F. Liu, C. Y. Jin
https://arxiv.org/abs/2507.02460

Enhancing Photon Indistinguishability of Spectrally Mismatched Single Photons by Cavity Floquet Engineering
We theoretically propose a scheme to enhance the photon indistinguishability of spectrally mismatched single photons via Floquet-engineered optical frequency combs (OFCs) in cavity quantum electrodynamic systems. By periodically modulating two distinct single-photon states under a modulation frequency which is exactly equal to the spectral mismatch of two cavity modes, a pair of single-photon frequency-comb (SPFC) states is prepared energy-conservatively based on full unitary operations. The tw…

The Missing Hard Photons of Little Red Dots: Their Incident Ionizing Spectra Resemble Massive Stars
Bingjie Wang, Joel Leja, Harley Katz, Kohei Inayoshi, Nikko J. Cleri, Anna de Graaff, Raphael E. Hviding, Pieter van Dokkum, Jenny E. Greene, Ivo Labb\'e, Jorryt Matthee, Ian McConachie, Rohan P. Naidu, Erica J. Nelson
https://arxiv.org/…

The Missing Hard Photons of Little Red Dots: Their Incident Ionizing Spectra Resemble Massive Stars
The nature of Little Red Dots (LRDs) has largely been investigated through their continuum emission, with lines assumed to arise from a broad-line region. In this paper, we instead use recombination lines to infer the intrinsic properties of the central engine of LRDs. Our analysis first reveals a tension between the ionizing properties implied from H$α$ and HeII$\,λ$4686. The high H$α$ EWs require copious H-ionizing photons, more than the bluest AGN ionizing spectra can provide. In contrast…

Simple explanation of apparent Bell nonlocality of unentangled photons
Antoni W\'ojcik, Jan W\'ojcik
https://arxiv.org/abs/2509.03127 https://arxiv…

Simple explanation of apparent Bell nonlocality of unentangled photons
Wang et al. [Science Advances, 1 Aug 2025 Vol 11, Issue 31] recently reported an experiment that they interpret as demonstrating a violation of Bell's inequality using unentangled photons. Such a claim is highly controversial, since it is well established that product states cannot surpass the bounds set by local hidden variable models. In this manuscript, we analyze the essential features of the experiment through simplified, idealized scenarios. Our analysis shows that the apparent violation …

Tribute to Henry Primakoff: Chiral Perturbation Theory Tests via Primakoff Reactions
Murray Moinester
https://arxiv.org/abs/2509.04649 https://arxiv.org/pd…

Tribute to Henry Primakoff: Chiral Perturbation Theory Tests via Primakoff Reactions
Consider the scattering of GeV energy beam particles off the Coulomb field of a nucleus. In this context, the Coulomb field behaves like a target of $γ^*$ virtual photons, with the target density being proportional to Z$^2$. Henry Primakoff was the first to describe how to determine the $π^0$ lifetime by measuring the production cross section for the process $γγ^* \rightarrow π^0$. When a $γ$ ray beam is used, Primakoff scattering is effectively represents $γγ^*$ scattering involving hu…

Integrated bright source of polarization-entangled photons using lithium niobate photonic chips
Changhyun Kim, Hansol Kim, Minho Choi, Junhyung Lee, Yongchan Park, Sunghyun Moon, Jinil Lee, Hyeon Hwang, Min-Kyo Seo, Yoon-Ho Kim, Yong-Su Kim, Hojoong Jung, Hyounghan Kwon
https://arxiv.org/abs/2506.23625

Integrated bright source of polarization-entangled photons using lithium niobate photonic chips
Quantum photonics has rapidly advanced as a key area for developing quantum technologies by harnessing photons' inherent quantum characteristics, particularly entanglement. Generation of entangled photon pairs, known as Bell states, is crucial for quantum communications, precision sensing, and quantum computing. While bulk quantum optical setups have provided foundational progress, integrated quantum photonic platforms now offer superior scalability, efficiency, and integrative potential. In th…

Orbital angular momentum of entangled photons as a probe for relativistic effects
Fazilah Nothlawala, Kiki Dekkers, Moslem Mahdavifar, Jonathan Leach, Andrew Forbes, Isaac Nape
https://arxiv.org/abs/2508.01716

Orbital angular momentum of entangled photons as a probe for relativistic effects
Orbital angular momentum (OAM) as both classical and quantum states of light has proven essential in numerous applications, from high-capacity information transfer to enhanced precision and accuracy in metrology. Here, we extend OAM metrology to relativistic scenarios to determine the Lorentz factor of a moving reference frame, exploiting the fact that OAM is not Lorentz invariant. Using OAM correlations of entangled states, we show that their joint OAM spectrum is modified by length contractio…

Directional Flow of Confined Polaritons in CrSBr
Pratap Chandra Adak, Sichao Yu, Jaime Abad-Arredondo, Biswajit Datta, Andy Cruz, Sorah Fischer, Kseniia Mosina, Zden\v{e}k Sofer, Antonio I. Fern\'andez-Dom\'inguez, Francisco J. Garc\'ia-Vidal, Vinod M. Menon
https://arxiv.org/abs/2507.04367

Directional Flow of Confined Polaritons in CrSBr
Nanoscale control of energy transport is a central challenge in modern photonics. Utilization of exciton-polaritons hybrid light-matter quasiparticles is one viable approach, but it typically demands complex device engineering to enable directional transport. Here, we demonstrate that the van der Waals magnet CrSBr offers an inherent avenue for steering polariton transport leveraging a unique combination of intrinsic optical anisotropy, high refractive index, and excitons dressed by photons. Th…

Axion-Photon Conversion In Magnetized Universe: Impact On The Global 21-cm Signal
Pravin Kumar Natwariya, Vivekanand Mohapatra, Hriditi Howlader
https://arxiv.org/abs/2509.04237

Axion-Photon Conversion In Magnetized Universe: Impact On The Global 21-cm Signal
The reported anomalous global 21-cm signal $(T_{21})$ from the cosmic dawn era by Experiment to Detect the Global Epoch of Reionisation Signature (EDGES) could hint towards new physics beyond the standard model. The resonant conversion of the axion-like particles (ALPs) into photons in the presence of primordial magnetic fields (PMFs) could be a viable solution. However, the strength of the PMFs can change over the time as they can decay by ambipolar diffusion and turbulent decay. Consequently,…

Bipartite entanglement in a nuclear spin register mediated by a quasi-free electron spin
Marco Klotz, Andreas Tangemann, David Opferkuch, Alexander Kubanek
https://arxiv.org/abs/2508.05255

Bipartite entanglement in a nuclear spin register mediated by a quasi-free electron spin
Quantum networks will rely on photons entangled to robust, local quantum registers for computation and error correction. We demonstrate control of and entanglement in a fully connected three-qubit $^{13}\mathrm{C}$ nuclear spin register in diamond. The register is coupled to a quasi-free electron spin-1/2 of a silicon-vacancy center (SiV). High strain decouples the SiVs electron spin from spin-orbit interaction reducing the susceptibility to phonons at liquid helium temperature. As a result, th…

Anomalous transparency of photons in non-Markovian coupled waveguides
J. R. Silva, P. A. Brand\~ao
https://arxiv.org/abs/2508.18028 https://arxiv.org/pdf/2…

Anomalous transparency of photons in non-Markovian coupled waveguides
The transmission of photons through a pair of coupled single-mode waveguides is studied in detail. It is assumed that one of the waveguides is coupled to a non-Markovian reservoir, described by a Lorentzian spectrum distribution. We identified four distinct regimes for the transmission coefficient and found that, in some conditions, it is more efficient to launch the photons in the lossy waveguide to achieve high transmission. We also report on a loss-induced transparency effect that is induced…

Proposal for High-Dimensional Entanglement Swapping with Linear Optics and Ancillary Photons
Baghdasar Baghdasaryan, Kaushik Joarder, Fabian Steinlechner
https://arxiv.org/abs/2509.02817

Proposal for High-Dimensional Entanglement Swapping with Linear Optics and Ancillary Photons
Quantum teleportation and entanglement swapping are fundamental building blocks for realizing global quantum networks. Both protocols have been extensively studied and experimentally demonstrated using two-dimensional qubit systems. Their implementation in high-dimensional (HD) systems offers significant advantages, such as enhanced noise resilience, greater robustness against eavesdropping, and increased information capacity. Generally, HD photonic entanglement swapping requires ancilla photon…

Bounding anisotropic Lorentz Invariance Violation from measurements of the effective energy scale of quantum gravity
Merce Guerrero, Anna Campoy-Ordaz, Robertus Potting, Markus Gaug
https://arxiv.org/abs/2508.02883

Bounding anisotropic Lorentz Invariance Violation from measurements of the effective energy scale of quantum gravity
Observations of energy-dependent photon time delays from distant flaring sources provide significant constraints on Lorentz Invariance Violation (LIV). Such effects originate from modified vacuum dispersion relations, causing differences in propagation times for photons emitted simultaneously from gamma-ray bursts, active galactic nuclei, or pulsars. These modifications are often parametrized within a general framework by an effective quantum gravity energy scale $E_{QG,n}$. While such general …

Optimal distillation of photonic indistinguishability
Francesco Hoch, Anita Camillini, Giovanni Rodari, Eugenio Caruccio, Gonzalo Carvacho, Taira Giordani, Riccardo Albiero, Niki Di Giano, Giacomo Corrielli, Francesco Ceccarelli, Roberto Osellame, Marco Robbio, Leonardo Novo, Nicol\`o Spagnolo, Ernesto F. Galv\~ao, Fabio Sciarrino
https://…

Optimal distillation of photonic indistinguishability
Imperfect photons' indistinguishability limits the performance of photonic quantum communication and computation . Distillation protocols, inspired by entanglement purification, enhance photons' indistinguishability by leveraging quantum interference in linear optical circuits. In this work, we present a three-photon distillation protocol optimized to achieve the maximum visibility gain, which requires consideration of multi-photon effects such as collective photonic phases. We employ interfero…

Quantum and Material Effects in Undulator-Based LSW Searches for Dark Photons
Wen Yin
https://arxiv.org/abs/2507.22055 https://arxiv.org/pdf/2507.22055

Quantum and Material Effects in Undulator-Based LSW Searches for Dark Photons
The dark photon is one of the simplest extensions of the Standard Model and provides a minimal laboratory for quantum-mechanical phenomena. Light-shining-through-a-wall (LSW) searches often adopt the dark photon-photon oscillation formula as if the sensitivity were independent of the light source, the wall, and the surrounding medium. In this paper, I revisit an LSW experiment whose light source is an undulator and systematically include various quantum effects: finite wave packets, kinematical…

Engineering Magnetization with Photons: Nanoscale Advances in the Inverse Faraday Effect for Metallic and Plasmonic Systems
Chantal Hareau, Xingyu Yang, Maria Sanz, Matthew Sheldon, Mathieu Mivelle
https://arxiv.org/abs/2506.23515

Engineering Magnetization with Photons: Nanoscale Advances in the Inverse Faraday Effect for Metallic and Plasmonic Systems
The inverse Faraday effect, the ability of light to act as a source of magnetism, is a cornerstone of modern ultrafast optics. Harnessing this effect at the nanoscale promises to transform data storage and spintronics, yet its predictive understanding remains elusive. This review synthesizes recent progress in engineering the IFE within plasmonic architectures. We bridge the theoretical foundations, from classical drift current models to quantum descriptions, with the latest experimental milest…

Effects of Bethe-Heitler pair production in ultraluminous X-ray sources
Gustavo Esteban Romero, Lucas Manuel Pasquevich, Leandro Abaroa
https://arxiv.org/abs/2509.03735 https://…

Effects of Bethe-Heitler pair production in ultraluminous X-ray sources
Some black holes in X-ray binaries accrete at rates far above the Eddington limit. In this supercritical regime, photons are trapped in a radiation-dominated, geometrically thick disk. The innermost regions form a complex environment of intense radiation, strong magnetic fields, and powerful outflows, where radiation-driven winds expel large amounts of mass. These conditions suppress primary relativistic electrons within the transparent funnel along the black hole's spin axis. We show that high…

Toward graviton detection via photon-graviton quantum state conversion
Taiki Ikeda, Youka Kaku, Sugumi Kanno, Jiro Soda
https://arxiv.org/abs/2507.01609 ht…

Toward graviton detection via photon-graviton quantum state conversion
A magnetic field enables the interconversion of photons and gravitons, yet the process is usually analysed only at the level of classical wave equations. We revisit photon-graviton conversion in a quantum field theoretic framework, allowing us to track the evolution of arbitrary quantum states. Treating the photons as squeezed coherent states and the gravitons as the squeezed vacuum expected for primordial gravitational waves, we derive analytic expressions for the conversion probability and sh…

Highly Efficient and Broadband Optical Delay Line towards a Quantum Memory
Yu Guo, Anindya Banerji, Jia Boon Chin, Arya Chowdhury, Alexander Ling
https://arxiv.org/abs/2509.02096

Highly Efficient and Broadband Optical Delay Line towards a Quantum Memory
We demonstrate a high-efficiency, free space optical delay line utilizing a nested multipass cell architecture. This design supports extended optical paths with low loss, aided by custom broadband dielectric coating that provides high reflectivity across a wide spectral bandwidth. The cell is characterized using polarization-entangled photon pairs, with signal photons routed through the delay line and idler photons used as timing reference. Quantum state tomography performed on the entangled pa…

Axion lines from nuclear de-excitations in galactic stellar populations
Orion Ning, Anupam Ray, Benjamin R. Safdi
https://arxiv.org/abs/2509.03569 https://…

Axion lines from nuclear de-excitations in galactic stellar populations
We show that mono-energetic axions are produced in abundance through nuclear de-excitations in nearby galaxies such as M87, which is the central galaxy of the Virgo cluster, and the starburst galaxy M82. If the axion couples to both nucleons and photons and is ultralight, then monochromatic hard X-ray signatures are induced by the subsequent axion-to-photon conversion in the magnetic fields permeating these systems. We search for evidence of such signals using NuSTAR data, focusing specifically…

Frequency conversion in topological plasmonic THz photo-mixer
Hamid Javadi
https://arxiv.org/abs/2508.03592 https://arxiv.org/pdf/2508.03592

Frequency conversion in topological plasmonic THz photo-mixer
We propose an alternative explanation for the observed coherent down-conversion in a laser-enabled plasmonic photo-mixer involving infrared, millimeter-wave, microwave photons. We will offer a path toward full experimental characterization of the device.

A broadband platform to search for hidden photons
Daqing Liu, Bin Tang, Xingfang Jiang, Xianyun Liu, Ning Ma
https://arxiv.org/abs/2506.19449 https://

A broadband platform to search for hidden photons
The optical behavior of a structure consisting of graphene sheets embedded in media was studied, and the differences between the structure and ordinary birefringent crystal, double zero-reflectance point, were identified. We showed the changes in the optical behavior of the structure due to the existence of hidden photons. When a radiation illuminates the structure, only $ω^2/ω_p^2>1+\frac{m_X^2 c^4 χ^2}{ε_r\hbar^2ω_p^2}$ can propagate through the structure. This provides a broadband platf…

General quantum computation on photons assisted with double single-sided cavity system
Jiu-Ming Li, Jun-Yan Liu, Yuan-Yuan Liu, Xiao-Ming Xiu, Shao-Ming Fei
https://arxiv.org/abs/2507.22773

General quantum computation on photons assisted with double single-sided cavity system
We propose a physical system consisting of two optical cavities and a two-level system (TLS), which can be viewed as a double single-sided cavity system. The two cavities are crossed each other in a mutually perpendicular way and are both single-sided. The TLS is coupled to the two cavities. The universal input-output relation of the system, the reflection and transmission coefficients are derived by exploiting the probability amplitude method. Then by using the nitrogen-vacancy center instead …

Multipolar transitions excited by twisted photons in heavy quarkonia
P. S. Korolev, V. A. Ryakin
https://arxiv.org/abs/2508.09877 https://arxiv.org/pdf/250…

Multipolar transitions excited by twisted photons in heavy quarkonia
In this study, we investigate the excitation of multipole transitions in quarkonium systems by high-energy photons carrying orbital angular momentum. We derive explicit expressions for the amplitude and probability of photoexcitation incorporating the dynamics of the quarkonium center of mass. It is shown that the leading contribution to the transitions induced by twisted photons comes from the multipole $j=|m_γ|$ and $m_γ=l'-l$ in the long-wave approximation. Despite the fact that …

Quantum Interference of Distinguishable Photons Based on Spatially-Resolved Measurements
Miguel Angel Gonzalez, Alejandra Alarc\'on, Andres Camilo Quintero, Daniel Sabogal, Luca Maggio, Vincenzo Tamma, Daniel F. Urrego, Alejandra Valencia
https://arxiv.org/abs/2508.14845

Quantum Interference of Distinguishable Photons Based on Spatially-Resolved Measurements
We present experimental results demonstrating the quantum interference of two photons distinguishable in their transverse momenta, each entering the input ports of a balanced beam splitter. This counterintuitive interference effect is made possible through spatially resolved measurements in the near field, i.e., by resolving the conjugate variable in which the photons are distinguishable. Our experimental findings agree with theoretical predictions. We contrast our results with a non-spatially …

Charge asymmetry in the process $e^ e^-\to \pi^ \pi^-\pi^0\gamma$
I. V. Obraztsov, A. S. Rudenko, A. I. Milstein
https://arxiv.org/abs/2509.03245 https://a…

Charge asymmetry in the process $e^+e^-\to π^+π^-π^0γ$
The charge asymmetry in the process $e^+e^-\to π^+π^-π^0γ$ is studied for photons with energies $ν\ll\sqrt{s}$. The longitudinal polarization of electrons (positrons) is taken into account. The asymmetry arises due to interference of the amplitudes for production of pion states with opposite $C$ parities. The contribution of $a_1^0(1260)$ meson in the intermediate state to the charge asymmetry is discussed. This contribution is not the leading one, however it is not negligible. It is shown…

Macroscopic entanglement between localized domain walls inside a cavity
Rahul Gupta, Huaiyang Yuan, Himadri Shekhar Dhar
https://arxiv.org/abs/2508.03450 https://

Macroscopic entanglement between localized domain walls inside a cavity
We present a scheme for generating stable and tunable entanglement between two localized Bloch domain walls in nanomagnetic strips kept inside a chiral optical cavity. The entanglement is mediated by the effective optomechanical interaction between the cavity photons and the two macroscopic, collective modes of the pinned domain walls. By controlling the pinning potential and optical driving frequency, the robust, steady-state entanglement between the two macroscopic domain walls can survive be…

INTEGRAL, eROSITA and Voyager Constraints on Light Bosonic Dark Matter: ALPs, Dark Photons, Scalars, $B-L$ and $L_{i}-L_{j}$ Vectors
Thong T. Q. Nguyen, Pedro De la Torre Luque, Isabelle John, Shyam Balaji, Pierluca Carenza, Tim Linden
https://arxiv.org/abs/2507.13432

INTEGRAL, eROSITA and Voyager Constraints on Light Bosonic Dark Matter: ALPs, Dark Photons, Scalars, $B-L$ and $L_{i}-L_{j}$ Vectors
The decay of light bosonic dark matter particles can produce a bright electron/positron ($e^+e^-$) flux that can be strongly constrained by local Voyager observations of the direct $e^+e^-$ flux, as well as 511 keV Line and X-ray continuum observations of $e^+e^-$ emission. We carefully analyze the $e^+e^-$ yield and resulting cosmic-ray and X-ray spectra from theoretically well-motivated light dark matter models, including: (a) electrophilic axion-like particles, (b) dark photons, (c) scalars,…

Dark Matter Haloscope with a Disordered Dielectric Absorber
Stewart Koppell, Otavio D. A. R. Bittencourt, Dip Joti Paul, Junwu Huang, Masha Baryakhtar, Karl K. Berggren
https://arxiv.org/abs/2506.00115

Dark Matter Haloscope with a Disordered Dielectric Absorber
Light dark matter candidates such as axions and dark photons generically couple to electromagnetism, yielding dark-matter-to-photon conversion as a key search strategy. In addition to resonant conversion in cavities and circuits, light dark matter bosons efficiently convert to photons on material interfaces, with a broadband power proportional to the total area of these interfaces. In this work, we make use of interface conversion to develop a new experimental dark matter detector design: the d…

Jones Matrix Reconstruction with Undetected Photons
Gaytri Arya, Paolo Bianchini, Alberto Diaspro
https://arxiv.org/abs/2507.20617 https://arxiv.org/pdf/25…

Jones Matrix Reconstruction with Undetected Photons
We present a theoretical polarization tomography scheme within the QIUP framework that directly extracts key sample parameters from measured interference visibilities and phase shifts. This approach establishes constant bindings for transmission amplitudes and coherence terms, thereby reducing the number of unknowns required to reconstruct the sample's Jones matrix. Our method is resource-efficient and well-suited for quantum imaging where probing and detection occur at different wavelengths, e…

Ultrastable, low-error dynamic polarization encoding of deterministically generated single photons
Joscha Hanel, Zenghui Jiang, Jipeng Wang, Frederik Benthin, Tom Fandrich, Eddy Patrick Rugeramigabo, Raphael Joos, Michael Jetter, Simone Luca Portalupi, Jingzhong Yang, Michael Zopf, Peter Michler, Fei Ding
https://arxiv.org/abs/2…

Ultrastable, low-error dynamic polarization encoding of deterministically generated single photons
The ability to inscribe information on single photons at high speeds is a crucial requirement for quantum applications such as quantum communication and measurement-based photonic quantum computation. Nowadays, most experimental implementations employ phase modulators in single-pass, Mach-Zehnder interferometer or Michelson interferometer configurations to encode information on photonic qubits. However, these approaches are intrinsically sensitive to environmental influences, limiting the achie…

Polarization-Controlled Dual-State Distribution of Bell and N00N Entanglement Over a Metro-Scale Commercial Quantum Network
Kazi Reaz, Md Mehdi Hassan, Jacob E. Humberd, Matthew L. Boone, Angel Fraire Estrada, Rick Mukherjee, H. R. Sadeghpour, Girish S. Agarwal, George Siopsis, Tian Li
https://arxiv.org/abs/2509.03701

Polarization-Controlled Dual-State Distribution of Bell and N00N Entanglement Over a Metro-Scale Commercial Quantum Network
We report the first demonstration of multiphoton, dual state entanglement distribution over a metropolitan scale commercial fiber network, implemented on the EPB Bohr IV quantum network in Chattanooga, TN, using an all fiber optic experimental platform. Employing a spatially degenerate, continuous wave type II SPDC biphoton source and fully fiber coupled linear optics, we generated a 4 photon entangled state. Through polarization projective measurements on two locally retained photons, we then …

Noise-tolerant tomography of multimode linear optical interferometers with single photons
Yu. A. Biriukov, R. D. Morozov, I. V. Dyakonov, M. V. Rakhlin, A. I. Galimov, G. V. Klimko, S. V. Sorokin, I. V. Sedova, M. M. Kulagina, Yu. M. Zadiranov, A. A. Toropov, A. A. Korneev, S. P. Kulik, S. S. Straupe
https://arxiv.org/abs/2506.2…

Noise-tolerant tomography of multimode linear optical interferometers with single photons
Linear optical networks are fundamental to the advancement of quantum technologies, including quantum computing, communication, and sensing. The accurate characterization of these networks, described by unitary matrices, is crucial to their effective utilization and scalability. In this work, we present the method for reconstructing the transfer matrix of a linear optical interferometer based on the analysis of cross-correlation functions of photon counts between pairs of output modes. Our appr…

Spontaneous emission as a bridge from Lindbladian to nonreciprocal reservoirs
C. J. Bolech, T. Giamarchi
https://arxiv.org/abs/2508.00689 https://arxiv.org…

Spontaneous emission as a bridge from Lindbladian to nonreciprocal reservoirs
We study an out-of-equilibrium quantum system in which a state connecting two reservoirs is also coupled by stimulated and spontaneous emission of photons to an antitrapped state, thus implementing particle loss. After revisiting the spontaneous emission process, we show that the proper effective description of such a system requires one to go beyond the usual Lindbladian formalism and includes a nonreciprocal (``non-Hermitian'') coupling to the reservoir modeling the untrapped state. The prese…

Counter-propagating spontaneous parametric down-conversion source in lithium niobate on insulator
Jost Kellner, Alessandra Sabatti, Tristan Kuttner, Robert J. Chapman, Rachel Grange
https://arxiv.org/abs/2506.21396

Counter-propagating spontaneous parametric down-conversion source in lithium niobate on insulator
Quantum photonic technologies rely on the ability to generate, manipulate, and interfere indistinguishable single photons on a scalable platform. Among the various approaches, spontaneous parametric down-conversion (SPDC) remains one of the most widely used methods for generating entangled or pure photon pairs. However most integrated SPDC sources relying on co-propagating geometries have a limited purity of heralded photons, or require lossy filtering. Type-2 SPDC processes can produce pure se…

Characterizing a high-dimensional unitary transformation without measuring the qudit it transforms
Salini Rajeev, Mayukh Lahiri
https://arxiv.org/abs/2509.02816 https://

Characterizing a high-dimensional unitary transformation without measuring the qudit it transforms
We present a method for reconstructing an arbitrary high-dimensional unitary transformation without detecting the qudit that it transforms. We demonstrate the method using orbital angular momentum states of light. Our method relies on quantum interference enabled by path identity of undetected photons. The method is practically useful when suitable detectors are not available for the qudit on which the unitary transformation works.

Is the EPR paradox really a paradox?
Natalia Gorobey, Alexander Lukyanenko
https://arxiv.org/abs/2509.02085 https://arxiv.org/pdf/2509.02085

Is the EPR paradox really a paradox?
If the excitation of a system of quantized fields with a given set of quantum numbers does not exist, the amplitude of the triggering of the source is zero. A system with a source of two photons in a singlet state and two photon detectors is considered in detail. It is shown that the condition of operation of one detector with a given direction of photon polarization uniquely determines the adequate choice of direction and polarization for the second detector. This conclusion is in accordance w…

Silicon single-photon detector achieving over 84% photon detection efficiency with flexible operation modes
Dong An, Chao Yu, Ming-Yang Zheng, Anran Guo, Junsong Wang, Ruizhi Li, Huaping Ma, Xiu-Ping Xie, Xiao-Hui Bao, Qiang Zhang, Jun Zhang, Jian-Wei Pan
https://arxiv.org/abs/2507.18172

Silicon single-photon detector achieving over 84% photon detection efficiency with flexible operation modes
Silicon single-photon detectors (Si SPDs) play a crucial role in detecting single photons in the visible spectrum. For various applications, photon detection efficiency (PDE) is the most critical characteristic for effectively collecting photons. Here, we present a Si SPD with a remarkable PDE of up to 84.4% at 785 nm, supporting multiple operation modes. We design and fabricate a thick-junction Si single-photon avalanche diode (SPAD) that enhances the avalanche probability through a backside-i…

Electrically pumped ultrabright entangled photons on chip
Xu-Feng Jiao, Ming-Yang Zheng, Yi-Hang Chen, Bo Cao, Xina Wang, Yang Liu, Cheng-Ao Yang, Xiu-Ping Xie, Chao-Yang Lu, Zhi-Chuan Niu, Qiang Zhang, Jian-Wei Pan
https://arxiv.org/abs/2508.14566

Electrically pumped ultrabright entangled photons on chip
Entangled photon sources (EPS) are essential for quantum science and technology. Despite advancements in integrated optical platforms like thin-film lithium niobate, a scalable, high-performance, chip-scale EPS has remained elusive. We address this by demonstrating an electrically pumped, post-selection-free polarization-EPS, achieved through hybrid integration of a distributed feedback laser with thin-film lithium niobate chip which integrates periodically poled lithium niobate waveguides, bea…