Tootfinder

Special-Unitary Parameterization for Trainable Variational Quantum Circuits
Kuan-Cheng Chen, Huan-Hsin Tseng, Samuel Yen-Chi Chen, Chen-Yu Liu, Kin K. Leung
https://arxiv.org/abs/2507.05535

Special-Unitary Parameterization for Trainable Variational Quantum Circuits
We propose SUN-VQC, a variational-circuit architecture whose elementary layers are single exponentials of a symmetry-restricted Lie subgroup, $\mathrm{SU}(2^{k}) \subset \mathrm{SU}(2^{n})$ with $k \ll n$. Confining the evolution to this compact subspace reduces the dynamical Lie-algebra dimension from $\mathcal{O}(4^{n})$ to $\mathcal{O}(4^{k})$, ensuring only polynomial suppression of gradient variance and circumventing barren plateaus that plague hardware-efficient ansätze. Exact, hardware-…

Oder aber, Lise Meitner hatte einfach einen verdammt guten Humor. 😏

Spherical Poisson Needlets with Shrinking Bandwidth
Mattia Castaldo, Claudio Durastanti
https://arxiv.org/abs/2507.05072 https://arxi…

Spherical Poisson Needlets with Shrinking Bandwidth
Flexible bandwidth needlets provide a localized multiscale framework with scale-adaptive frequency resolution, enabling effective analysis of spherical Poisson random fields exhibiting spatial inhomogeneity and scale variation. We establish here quantitative Central Limit Theorems for finite-dimensional distributions of spherical Poisson needlets and for the related Poisson needlet coefficients constructed via needlets with shrinking bandwidth on the sphere, and using Stein-Malliavin techniques…

Instanton Moduli, Topology and the Bosonic/Heterotic String Origins
Liang Ma, H. Lu
https://arxiv.org/abs/2507.05351 https://arxiv.or…

Instanton Moduli, Topology and the Bosonic/Heterotic String Origins
We construct new supersymmetric NS(-1)-branes supported by the $SU(2)\times SU(2)$ 't Hooft instantons in ${\cal N}=1$, $D=4$ supergravity. We show that although the magnetic 3-form string flux is invariant under the variation of instanton moduli, the string-frame metric can change topology, giving rise to either $\mathbb R^4$ or the new $\mathbb R\times S^3$ bolt topologies. We uplift the solutions to both heterotic and bosonic strings, where the instanton moduli become parameters of pure geom…

Sparse Gaussian Processes: Structured Approximations and Power-EP Revisited
Thang D. Bui, Michalis K. Titsias
https://arxiv.org/abs/2507.02377 https://

Sparse Gaussian Processes: Structured Approximations and Power-EP Revisited
Inducing-point-based sparse variational Gaussian processes have become the standard workhorse for scaling up GP models. Recent advances show that these methods can be improved by introducing a diagonal scaling matrix to the conditional posterior density given the inducing points. This paper first considers an extension that employs a block-diagonal structure for the scaling matrix, provably tightening the variational lower bound. We then revisit the unifying framework of sparse GPs based on Pow…

Unrolling Nonconvex Graph Total Variation for Image Denoising
Songlin Wei, Gene Cheung, Fei Chen, Ivan Selesnick
https://arxiv.org/abs/2506.02381 https://

Unrolling Nonconvex Graph Total Variation for Image Denoising
Conventional model-based image denoising optimizations employ convex regularization terms, such as total variation (TV) that convexifies the $\ell_0$-norm to promote sparse signal representation. Instead, we propose a new non-convex total variation term in a graph setting (NC-GTV), such that when combined with an $\ell_2$-norm fidelity term for denoising, leads to a convex objective with no extraneous local minima. We define NC-GTV using a new graph variant of the Huber function, interpretable …

US-General Grynkewich wird neuer NATO-Militärchef
Der US-General Alexus Grynkewich wird neuer Oberbefehlshaber der NATO-Truppen in Europa. Der Nordatlantikrat stimmte seiner Nominierung in Brüssel zu, wie eine Sprecherin der Militärallianz auf der Online-Plattform X mitteilte. Grynkewich übernimmt die Militärführung der NATO im vierten Jahr des Ukraine-Krieges und zum Zeitpunkt massiver Aufrüstung in Europa.
Im Sommer soll G…
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Ukraine-Liveblog: ++ Satellitenbilder zeigen Schäden an Flugzeugen ++
Nach dem ukrainischen Angriff vom Sonntag auf russische Militärstützpunkte sind auf Satellitenbildern Schäden an einigen Maschinen zu sehen. Im Norden der Ukraine sind bei Angriffen laut Behörden mindestens fünf Menschen getötet worden. Der Liveblog vom Donnerstag zum Nachlesen.

🇺🇦 #NowPlaying on KEXP's #VarietyMix
Hidden Spheres:
🎵 Promised Me Love
#HiddenSpheres
https://open.spotify.com/track/6b5NKD3dNcwNs2RzMZvjE2

Dynamic formation of supersolid phase in a mixture of ultracold bosonic and fermionic atoms
Maciej Lewkowicz, Tomasz Karpiuk, Mariusz Gajda, Miros{\l}aw Brewczyk
https://arxiv.org/abs/2506.03717

Dynamic formation of supersolid phase in a mixture of ultracold bosonic and fermionic atoms
We numerically study the dynamical properties of a mixture consisting of a dipolar condensate and a degenerate Fermi gas in a quasi-one-dimensional geometry. In particular, we focus on the system's response to a temporal variation in the interaction strength between bosons and fermions. When the interspecies attraction becomes sufficiently strong, we observe a phase transition to a supersolid state. This conclusion is supported by the emergence of an out-of-phase Goldstone mode in the excitatio…

Hyperspherical Variational Autoencoders Using Efficient Spherical Cauchy Distribution
Lukas Sablica, Kurt Hornik
https://arxiv.org/abs/2506.21278 https://

Hyperspherical Variational Autoencoders Using Efficient Spherical Cauchy Distribution
We propose a novel variational autoencoder (VAE) architecture that employs a spherical Cauchy (spCauchy) latent distribution. Unlike traditional Gaussian latent spaces or the widely used von Mises-Fisher (vMF) distribution, spCauchy provides a more natural hyperspherical representation of latent variables, better capturing directional data while maintaining flexibility. Its heavy-tailed nature prevents over-regularization, ensuring efficient latent space utilization while offering a more expres…