Tootfinder

Submodular Maximization over a Matroid $k$-Intersection: Multiplicative Improvement over Greedy
Moran Feldman, Justin Ward
https://arxiv.org/abs/2602.08473 https://arxiv.org/pdf/2602.08473 https://arxiv.org/html/2602.08473
arXiv:2602.08473v1 Announce Type: new
Abstract: We study the problem of maximizing a non-negative monotone submodular objective $f$ subject to the intersection of $k$ arbitrary matroid constraints. The natural greedy algorithm guarantees $(k 1)$-approximation for this problem, and the state-of-the-art algorithm only improves this approximation ratio to $k$. We give a $\frac{2k\ln2}{1 \ln2} O(\sqrt{k})<0.819k O(\sqrt{k})$ approximation for this problem. Our result is the first multiplicative improvement over the approximation ratio of the greedy algorithm for general $k$. We further show that our algorithm can be used to obtain roughly the same approximation ratio also for the more general problem in which the objective is not guaranteed to be monotone (the sublinear term in the approximation ratio becomes $O(k^{2/3})$ rather than $O(\sqrt{k})$ in this case).
All of our results hold also when the $k$-matroid intersection constraint is replaced with a more general matroid $k$-parity constraint. Furthermore, unlike the case in many of the previous works, our algorithms run in time that is independent of $k$ and polynomial in the size of the ground set. Our algorithms are based on a hybrid greedy local search approach recently introduced by Singer and Thiery (STOC 2025) for the weighted matroid $k$-intersection problem, which is a special case of the problem we consider. Leveraging their approach in the submodular setting requires several non-trivial insights and algorithmic modifications since the marginals of a submodular function $f$, which correspond to the weights in the weighted case, are not independent of the algorithm's internal randomness. In the special weighted case studied by Singer and Thiery, our algorithms reduce to a variant of their algorithm with an improved approximation ratio of $k\ln2 1-\ln2<0.694k 0.307$, compared to an approximation ratio of $\frac{k 1}{2\ln2}\approx0.722k 0.722$ guaranteed by Singer and Thiery.
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Atomic and molecular systems for radiation thermometry
Stephen P. Eckel, Eric B. Norrgard, Christopher Holloway, Nikunjkumar Prajapati, Noah Schlossberger, Matthew Simons
https://arxiv.org/abs/2512.08668 https://arxiv.org/pdf/2512.08668 https://arxiv.org/html/2512.08668
arXiv:2512.08668v1 Announce Type: new
Abstract: Atoms and simple molecules are excellent candidates for new standards and sensors because they are both all identical and their properties are determined by the immutable laws of quantum physics. Here, we introduce the concept of building a standard and sensor of radiative temperature using atoms and molecules. Such standards are based on precise measurement of the rate at which blackbody radiation (BBR) either excites or stimulates emission for a given atomic transition. We summarize the recent results of two experiments while detailing the rate equation models required for their interpretation. The cold atom thermometer (CAT) uses a gas of laser cooled $^{85}$Rb Rydberg atoms to probe the BBR spectrum near 130~GHz. This primary, {\it i.e.}, not traceable to a measurement of like kind, temperature measurement currently has a total uncertainty of approximately 1~\%, with clear paths toward improvement. The compact blackbody radiation atomic sensor (CoBRAS) uses a vapour of $^{85}$Rb and monitors fluorescence from states that are either populated by BBR or populated by spontaneous emission to measure the blackbody spectrum near 24.5~THz. The CoBRAS has an excellent relative precision of $u(T)\approx 0.13$~K, with a clear path toward implementing a primary
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What if submarine fibre-optic cables could do more than carry data? SUBMERSE project is proving they can.
This EU-funded project brings together 25 consortium partners, from research groups to National Research and Education Networks (NRENs) and industry, including GÉANT and our member NRENs.
Together, we're exploring how existing telecom infrastructure can be transformed into scientific sensors.
🔗 Read more in the latest

Please — and I can't believe I have to say this — please do not lick your employees.

🇺🇦 #NowPlaying on KEXP's #SonicReducer
Dow Jones and the Industrials:
🎵 Ladies With Appliances
#DowJonesandtheIndustrials
https://thegizmos.bandcamp.com/track/ladies-with-appliances-dow-jones-the-industrials-bonus-red-snerts-track
https://open.spotify.com/track/7kmvjOA33cpowsiYWUPRIh

Abbott warnt vor fehlerhaften Sensoren: Blutzuckersensoren melden falsche Werte
Der US-amerikanische Hersteller Abbott warnt Kunden per Mail vor fehlerhaften Blutzuckersensoren. Die Geräte liefern zu niedrige Werte.
…

High-bandwidth frequency domain multiplexed readout of transition-edge sensors for neutrinoless double beta decay searches
M. Adami\v{c} (McGill,LBNL), M. Beretta (UCB,INFN), J. Camilleri (LBNL,Virginia Tech), C. Capelli (LBNL,Zurich U.), M. A. Dobbs (McGill), T. Elleflot (LBNL), B. K. Fujikawa (LBNL), Yu. G. Kolomensky (LBNL,UCB), D. Mayer (MIT), J. Montgomery (McGill), V. Novosad (ANL), A. M. Sindhwad (UCB), V. Singh (UCB), G. Smecher (t0.technology), A. Suzuki (LBNL), B. Welliver (UCB)
https://arxiv.org/abs/2601.23106 https://arxiv.org/pdf/2601.23106 https://arxiv.org/html/2601.23106
arXiv:2601.23106v1 Announce Type: new
Abstract: The next-generation of cryogenic neutrinoless double-beta decay experiments require increasingly fast readout in order to improve background discrimination. These experiments, operated as cryogenic calorimeters at $\sim$10 mK, are usually read out by high-impedance neutron transmutation doped (NTD) thermistors, which provide good energy resolution, but are limited by $\sim$1 ms response times. Superconducting detectors, such as transition-edge sensors (TESs) with a time resolution of $\sim$100 $\mu$s, offer superior timing performance over NTD semiconductor bolometers. To make this technology viable for an application to a thousand or more channels, multiplexed readout is necessary in order to minimize the thermal load and radioactive contamination induced by the readout. Frequency-domain multiplexing readout (fMux) for TESs, previously developed at Berkeley Lab and McGill University, is currently in use for mm-wave telescopes with detector sampling rates in the order of 100 Hz. We demonstrate a new readout system, based on the McGill/Berkeley digital fMux readout, to satisfy the higher bandwidth and noise requirements of the next generation of TES-instrumented cryogenic calorimeters. The new readout samples detectors at 156 kHz, three orders of magnitude faster than its cosmology-oriented predecessor. Each multiplexing readout module comprises ten superconducting resonators in the MHz range and a superconducting quantum interference device (SQUID), interfaced to high-bandwidth field programmable gate array (FPGA)-based electronics for digital signal processing and low-latency feedback.
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Just so you know: a fascist is now running this country, openly pushing for Maduro to resign so his so-called “regime change” can install a literal fascist instead.
#Venezuela #USPol #Politics

Streit um KI-Klausel: Kommende Netflix-Originals ohne deutschen Ton?
Netflix stößt beim Versuch, sich das Recht einräumen zu lassen, Synchronaufnahmen für KI-Trainingszwecke zu nutzen, auf Widerstand des Sprecherbandes.