cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Entanglement Complexity in Quantum Many-Body Dynamics, Thermalization and Localization
Creators: name: Yang, Zhi-Cheng
name: Hamma, Alioscia
name: Giampaolo, Salvatore M.
name: Mucciolo, Eduardo R.
name: Chamon, Claudio
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Entanglement is usually quantified by von Neumann entropy, but its properties are much more complex than what can be expressed with a single number. We show that the three distinct dynamical phases known as thermalization, Anderson localization, and many-body localization are marked by different patterns of the spectrum of the reduced density matrix for a state evolved after a quantum quench. While the entanglement spectrum displays Poisson statistics for the case of Anderson localization, it displays universal Wigner-Dyson statistics for both the cases of many-body localization and thermalization, albeit the universal distribution is asymptotically reached within very different time scales in these two cases. We further show that the complexity of entanglement, revealed by the possibility of disentangling the state through a Metropolis-like algorithm, is signaled by whether the entanglement spectrum level spacing is Poisson or Wigner-Dyson distributed.
description: Minor revisions
Machine Learning for Microcontroller-Class Hardware: A Review
Creators: name: Saha, Swapnil Sayan
name: Sandha, Sandeep Singh
name: Srivastava, Mani
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: The advancements in machine learning opened a new opportunity to bring intelligence to the low-end Internet-of-Things nodes such as microcontrollers. Conventional machine learning deployment has high memory and compute footprint hindering their direct deployment on ultra resource-constrained microcontrollers. This paper highlights the unique requirements of enabling onboard machine learning for microcontroller class devices. Researchers use a specialized model development workflow for resource-limited applications to ensure the compute and latency budget is within the device limits while still maintaining the desired performance. We characterize a closed-loop widely applicable workflow of machine learning model development for microcontroller class devices and show that several classes of applications adopt a specific instance of it. We present both qualitative and numerical insights into different stages of model development by showcasing several use cases. Finally, we identify the open research challenges and unsolved questions demanding careful considerations moving forward.
description: Published in IEEE Sensors Journal. Cite this as: S. S. Saha, S. S. Sandha and M. Srivastava, "Machine Learning for Microcontroller-Class Hardware: A Review," in IEEE Sensors Journal, vol. 22, no. 22, pp. 21362-21390, 15 Nov., 2022
On-chip multiplexed multiple entanglement sources in a single silicon nanowire
Creators: name: Li, Yin-Hai
name: Zhou, Zhi-Yuan
name: Liu, Shi-long
name: Liu, Shi-Kai
name: Feng, Lan-Tian
name: Wang, Kai
name: Ren, Xi-Feng
name: Ding, Dong-Sheng
name: Xu, Li-Xin
name: Shi, Bao-Sen
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Silicon-on-chip (SOI) photonic circuit is the most promising platform for scalable quantum information technology for its low loss, small footprint, CMOS-compatible and telecom communications techniques compatible. Multiple multiplexed entanglement sources include: energy-time, time-bin and polarization entangled sources based on 1-cm length single silicon nanowire, all these sources are compatible with (100GHz) dense-wave-division-multiplexing (DWDM) system. Different methods such as two photon interference pattern, Bell-Inequality and quantum state tomography are used to characterize the quality of these entangled sources. Multiple entanglements are generated over more than 5 channel pairs with high raw (net) visibilities around 97% (100%). The emission spectral brightness of these entangled sources reaches 4.2*105 /(s.nm.mW). The quality of the photon pair generated in continuous and pulse pump regimes are compared. High qualities of these multiplexed entanglement sources make them very promising to be used in future minimized quantum communication and computation systems.
description: Accepted by Physical Review Applied
Heavy-light hybrid mesons with different spin-parities
Creators: name: Barsbay, B.
name: Azizi, K.
name: Sundu, H.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: The spectroscopic parameters of the heavy-light hybrid mesons with different spin-parities and different quark contents are investigated in the framework of the QCD sum rule method. The mass and current coupling of these states are calculated by taking into account the quark, gluon and mixed vacuum condensates up to dimension 10. The obtained results are compared with the existing QCD Laplace sum rule predictions. The results of mass and current coupling for all the considered channels are obtained to be stable and reliable. Our results can be useful for future experimental searches as well as theoretical studies of different parameters related to the hybrid mesons and their decays and interactions with other particles.
description: 12 Pages, 3 Figures and10 Tables
The long view of triadic resonance instability in finite-width internal gravity wave beams
Creators: name: Grayson, K. M.
name: Dalziel, Stuart B.
name: Lawrie, Andrew G. W.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: This paper presents our investigation into the modification of a finite-width internal gravity wave beam arising from triadic resonance instability. We present both experimental and weakly non-linear modelling to examine this instability mechanism, in which a primary wave beam generates two secondary wave beams of lower frequencies and shorter length scales. Through a versatile experimental set-up, we examine how this instability develops over hundreds of buoyancy periods. Unlike predictions from previous zero-dimensional weakly non-linear theory, we find that the approach to a saturated equilibrium state for the triadic interactions is not monotonic; rather, the amplitudes and structures of the constituent beams continue to modulate without ever reaching a steady equilibrium. To understand this behaviour we develop a weakly non-linear approach to account for the spatio-temporal evolution of the amplitudes and structures of the beams over slow time-scales and long distances, and explore the consequences using a numerical scheme. Through this approach, we establish that the evolution of the instability is remarkably sensitive to the spatio-temporal triadic configuration for the system and how part of the observed modulations can be attributed to a competition between the linear growth rate of the secondary wave beams and the finite residence time of the triadic perturbations within the underlying primary beam.
description: 34 pages, 14 figures. Submitted to the Journal of Fluid Mechanics
Space-time resolved quantum field approach to Klein tunneling dynamics across a finite barrier
Creators: name: Alkhateeb, M.
name: Matzkin, A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We investigate Klein tunneling through finite potential barriers with space-time resolved solutions to relativistic quantum field equations. We find that no particle actually tunnels through a finite supercritical barrier, even in the case of resonant tunneling. The transmission is instead mediated by modulations in pair production rates, at each edge of the barrier, caused by the incoming electron. We further examine the effect of the barrier's width on the numbers of produced pairs in the fermionic case (characterized by saturation) and in the bosonic case (characterized by exponential superradiance). This work paves the way to precise studies of the radiating dynamics of supercritical barriers, and could be applied to certain analogs of Klein tunneling observed in systems modeled by relativistic wave equations.
description: Slightly extended, one figure added
Conductance and Kondo Interference beyond Proportional Coupling
Creators: name: da Silva, Luis G. G. V. Dias
name: Lewenkopf, Caio H.
name: Vernek, Edson
name: Ferreira, Gerson J.
name: Ulloa, Sergio E.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The transport properties of nanostructured systems are deeply affected by the geometry of the effective connections to metallic leads. In this work we derive a conductance expression for interacting systems whose connectivity geometries do not meet the Meir-Wingreen proportional coupling condition. As an interesting application, we consider a quantum dot connected coherently to tunable electronic cavity modes. The structure is shown to exhibit a well-defined Kondo effect over a wide range of coupling strengths between the two subsystems. In agreement with recent experimental results, the calculated conductance curves exhibit strong modulations and asymmetric behavior as different cavity modes are swept through the Fermi level. These conductance modulations occur, however, while maintaining robust Kondo singlet correlations of the dot with the electronic reservoir, a direct consequence of the lopsided nature of the device.
description: Version published in PRL. 18 pages (4+1 pages + 13 pages of supplementary material)
CME dynamics using STEREO & LASCO observations: the relative importance of Lorentz forces and solar wind drag
Creators: name: Sachdeva, Nishtha
name: Subramanian, Prasad
name: Vourlidas, Angelos
name: Bothmer, Volker
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We seek to quantify the relative contributions of Lorentz forces and aerodynamic drag on the propagation of solar coronal mass ejections (CMEs). We use Graduated Cylindrical Shell (GCS) model fits to a representative set of 38 CMEs observed with the SOHO and STEREO spacecraft. We find that the Lorentz forces generally peak between 1.65 and 2.45 Rsun for all CMEs. For fast CMEs, Lorentz forces become negligible in comparison to aerodynamic drag as early as 3.5--4 Rsun. For slow CMEs, however, they become negligible only by 12--50 Rsun. For these slow events, our results suggest that some of the magnetic flux might be expended in CME expansion or heating. In other words, not all of it contributes to directed propagation. Our results are expected to be important in building a physical model for understanding the Sun-Earth dynamics of CMEs.
description: 21 pages, 7 figures, Accepted for publication in Topical Issue of Solar Physics- Earth-affecting solar transients
Isomonodromy for the Degenerate Fifth Painlevé Equation
Creators: name: Acosta-Humánez, Primitivo B.
name: van der Put, Marius
name: Top, Jaap
Publisher: name: arXiv
Year: 2016
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: 33E17, 14D20, 14D22, 34M55

description: This is a sequel to papers by the last two authors making the Riemann-Hilbert correspondence and isomonodromy explicit. For the degenerate fifth Painlevé equation, the moduli spaces for connections and for monodromy are explicitly computed. It is proven that the extended Riemann-Hilbert morphism is an isomorphism. As a consequence these equations have the Painlevé property and the Okamoto-Painlevé space is identified with a moduli space of connections. Using MAPLE computations, one obtains formulas for the degenerate fifth Painlevé equation, for the Bäcklund transformations.
Improved measurement of solar neutrinos from the Carbon-Nitrogen-Oxygen cycle by Borexino and its implications for the Standard Solar Model
Creators: name: Appel, S.
name: Bagdasarian, Z.
name: Basilico, D.
name: Bellini, G.
name: Benziger, J.
name: Biondi, R.
name: Caccianiga, B.
name: Calaprice, F.
name: Caminata, A.
name: Cavalcante, P.
name: Chepurnov, A.
name: D'Angelo, D.
name: Derbin, A.
name: Di Giacinto, A.
name: Di Marcello, V.
name: Ding, X. F.
name: Di Ludovico, A.
name: Di Noto, L.
name: Drachnev, I.
name: Franco, D.
name: Galbiati, C.
name: Ghiano, C.
name: Giammarchi, M.
name: Goretti, A.
name: Göttel, A. S.
name: Gromov, M.
name: Guffanti, D.
name: Ianni, Aldo
name: Ianni, Andrea
name: Jany, A.
name: Kobychev, V.
name: Korga, G.
name: Kumaran, S.
name: Laubenstein, M.
name: Litvinovich, E.
name: Lombardi, P.
name: Lomskaya, I.
name: Ludhova, L.
name: Lukyanchenko, G.
name: Machulin, I.
name: Martyn, J.
name: Meroni, E.
name: Miramonti, L.
name: Misiaszek, M.
name: Muratova, V.
name: Nugmanov, R.
name: Oberauer, L.
name: Orekhov, V.
name: Ortica, F.
name: Pallavicini, M.
name: Papp, L.
name: Pelicci, L.
name: Penek, Ö.
name: Pietrofaccia, L.
name: Pilipenko, N.
name: Pocar, A.
name: Raikov, G.
name: Ranalli, M. T.
name: Ranucci, G.
name: Razeto, A.
name: Re, A.
name: Redchuk, M.
name: Rossi, N.
name: Schönert, S.
name: Semenov, D.
name: Settanta, G.
name: Skorokhvatov, M.
name: Singhal, A.
name: Smirnov, O.
name: Sotnikov, A.
name: Tartaglia, R.
name: Testera, G.
name: Unzhakov, E.
name: Villante, F. L.
name: Vishneva, A.
name: Vogelaar, R. B.
name: von Feilitzsch, F.
name: Wojcik, M.
name: Wurm, M.
name: Zavatarelli, S.
name: Zuber, K.
name: Zuzel, G.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present an improved measurement of the CNO solar neutrino interaction rate at Earth obtained with the complete Borexino Phase-III dataset. The measured rate R$_{\rm CNO}$ = $6.7^{+2.0}_{-0.8}$ counts/(day$ \cdot$ 100 tonnes), allows us to exclude the absence of the CNO signal with about 7$σ$ C.L. The correspondent CNO neutrino flux is $6.6^{+2.0}_{-0.9} \times 10^8$ cm$^{-2}$ s$^{-1}$, taking into account the neutrino flavor conversion. We use the new CNO measurement to evaluate the C and N abundances in the Sun with respect to the H abundance for the first time with solar neutrinos. Our result of $N_{\rm CN}$ = $(5.78^{+1.86}_{-1.00})\times10^{-4}$ displays a $\sim$2$σ$ tension with the "low metallicity" spectroscopic photospheric measurements. On the other hand, our result used together with the $^7$Be and $^8$B solar neutrino fluxes, also measured by Borexino, permits to disfavour at 3.1$σ$ C.L. the "low metallicity" SSM B16-AGSS09met as an alternative to the "high metallicity" SSM B16-GS98.
description: 8 pages, 6 figures
Network Cards: concise, readable summaries of network data
Creators: name: Bagrow, James
name: Ahn, Yong-Yeol
Publisher: name: arXiv
Year: 2022
Subjects: subject: Social and Information Networks (cs.SI)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: The deluge of network datasets demands a standard way to effectively and succinctly summarize network datasets. Building on similar efforts to standardize the documentation of models and datasets in machine learning, here we propose network cards, short summaries of network datasets that can capture not only the basic statistics of the network but also information about the data construction process, provenance, ethical considerations, and other metadata. In this paper, we lay out (1) the rationales and objectives for network cards, (2) key elements that should be included in network cards, and (3) example network cards to underscore their benefits across a variety of research domains. We also provide a schema, templates, and a software package for generating network cards.
description: 16 pages, 6 tables
Phase Transitions and Baryogenesis From Decays
Creators: name: Shuve, Brian
name: Tamarit, Carlos
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study scenarios in which the baryon asymmetry is generated from the decay of a particle whose mass originates from the spontaneous breakdown of a symmetry. This is realized in many models, including low-scale leptogenesis and theories with classical scale invariance. Symmetry breaking in the early universe proceeds through a phase transition that gives the parent particle a time-dependent mass, which provides an additional departure from thermal equilibrium that could modify the efficiency of baryogenesis from out-of-equilibrium decays. We characterize the effects of various types of phase transitions and show that an enhancement in the baryon asymmetry from decays is possible if the phase transition is of the second order, although such models are typically fine-tuned. We also stress the role of new annihilation modes that deplete the parent particle abundance in models realizing such a phase transition, reducing the efficacy of baryogenesis. A proper treatment of baryogenesis in such models therefore requires the inclusion of the effects we study in this paper.
description: 39 pages (29 pages + Appendices), 8 figures. V2: corrected references, submitted to JHEP. V3: version published in JHEP
Fury: an experimental dynamo with anisotropic electrical conductivity
Creators: name: Alboussière, Thierry
name: Plunian, Franck
name: Moulin, Marc
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: We report measurements of dynamo action in a new experimental setup, named Fury, based on the use of an anisotropic electrical conductivity. It consists in a copper rotor rotating inside a copper stator, electrically connected with a thin layer of liquid metal, galinstan. Grooves have been cut in the copper so that, everywhere, electrical conductivity can be considered to be that of copper along two directions while it is zero along the third one. The configuration is efficient and dynamo action can be powered by hand. We have also used a motor with better control, enabling us to drive the rotor at specified velocity or torque functions of time. The structure of the axisymmetric magnetic field produced is found to be close to the numerical modelling using FreeFem++. The experimental dynamo behaves very nearly as expected for a kinematic dynamo, so that the threshold dynamo velocity cannot be exceeded, or only briefly. More mechanical power in the rotor rotation leads to an increase in the magnetic field intensity, the magnetic energy being proportional to the extra mechanical power beyond threshold. In the transient following a step increase of torque, magnetic and angular velocity oscillations have been observed and explained.
description: 19 pages, 9 figures. Data and data processing files can be found at https://mycore.core-cloud.net/index.php/s/ZuJ0zNp6JzLhVar
Critical end point in a thermo-magnetic nonlocal NJL model
Creators: name: Marquez, F.
name: Zamora, R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this article we explore the critical end point in the $T-μ$ phase diagram of a thermomagnetic nonlocal Nambu--Jona-Lasinio model in the weak field limit. We work with the Gaussian regulator, and find that a crossover takes place at $μ, B=0$. The crossover turns to a first order phase transition as the chemical potential or the magnetic field increase. The critical end point of the phase diagram occurs at a higher temperature and lower chemical potential as the magnetic field increases. This result is in accordance to similar findings in other effective models. We also find there is a critical magnetic field, for which a first order phase transition takes place even at $μ=0$.
description: Some changes as well as new references have been added. Accepted for publication in International Journal of Modern Physics A
Expanded solutions of force-free electrodynamics on general Kerr black holes
Creators: name: Li, Huiquan
name: Wang, Jiancheng
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this work, expanded solutions of force-free magnetospheres on general Kerr black holes are derived through a radial distance expansion method. From the regular conditions both at the horizon and at spatial infinity, two previously known asymptotical solutions (one of them is actually an exact solution) are identified as the only solutions that satisfy the same conditions at the two boundaries. Taking them as initial conditions at the boundaries, expanded solutions up to the first few orders are derived by solving the stream equation order by order. It is shown that our extension of the exact solution can (partially) cure the problems of the solution: it leads to magnetic domination and a mostly timelike current for restricted parameters.
description: 23 pages, 2 figures
Constraining $F(R)$ bouncing cosmologies with primordial black holes
Creators: name: Banerjee, Shreya
name: Papanikolaou, Theodoros
name: Saridakis, Emmanuel N.
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The phenomenology of primordial black hole (PBH) physics and the associated PBH abundance constraints, can be used in order to probe the physics of the early Universe. In this work, we investigate the PBH formation during the standard radiation-dominated era by studying the effect of an early F(R) modified gravity phase with a bouncing behavior which is introduced to avoid the initial spacetime singularity problem. In particular, we calculate the energy density power spectrum at horizon crossing time and then we extract the PBH abundance in the context of peak theory as a function of the parameter $α$ of our $F(R)$ gravity bouncing model at hand. Interestingly, we find that in order to avoid GW overproduction from an early PBH dominated era before Big Bang Nucleosynthesis (BBN), $α$ should lie within the range $α\leq 10^{-19}M^2_\mathrm{Pl}$. This constraint can be translated to a constraint on the energy scale at the onset of the Hot Big Bang (HBB) phase, $H_\mathrm{RD}\sim \sqrtα/2$ which can be recast as $H_\mathrm{RD}< 10^{-10}M_\mathrm{Pl}$.
description: To appear in Phys.Rev.D
Unitary Reconstruction of Secret for Stabilizer Based Quantum Secret Sharing
Creators: name: Matsumoto, Ryutaroh
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Information Theory (cs.IT)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences
subject: E.3
subject: 81P94, 94A62

description: We propose a unitary procedure to reconstruct quantum secret for a quantum secret sharing scheme constructed from stabilizer quantum error-correcting codes. Erasure correcting procedures for stabilizer codes need to add missing shares for reconstruction of quantum secret while unitary reconstruction procedures for certain class of quantum secret sharing are known to work without adding missing shares. The proposed procedure also works without adding missing shares.
description: svjour3.cls, 8 pages, no figure. To be published in Quantum Information Processing
Impact of carrier localization on recombination in InGaN quantum wells and the efficiency of nitride light-emitting diodes: insights from theory and numerical simulations
Creators: name: Jones, Christina
name: Teng, Chu-Hsiang
name: Yan, Qimin
name: Ku, Pei-Cheng
name: Kioupakis, Emmanouil
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We examine the effect of carrier localization due to random alloy fluctuations on the radiative and Auger recombination rates in InGaN quantum wells as a function of alloy composition, crystal orientation, carrier density, and temperature. Our results show that alloy fluctuations reduce individual transition matrix elements by the separate localization of electrons and holes, but this effect is overcompensated by the additional transitions enabled by translational symmetry breaking and the resulting lack of momentum conservation. Hence, we find that localization increases both radiative and Auger recombination rates, but that Auger recombination rates increase by one order of magnitude more than radiative rates. Furthermore, we demonstrate that localization has an overall detrimental effect on the efficiency-droop and green-gap problems of InGaN LEDs.
description: Main text is 7 pages and includes 6 figures. Supplementary information is 7 pages and includes 2 figures and 2 tables
Multiboson signals in the UN2HDM
Creators: name: Aguilar-Saavedra, J. A.
name: Joaquim, F. R.
name: Seabra, J. F.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We address multiboson production from a heavy $Z'$ resonance in the context of the UN2HDM, a standard model extension with an additional $\text{U}(1)'$ symmetry and an enlarged scalar sector with an extra doublet and a singlet. After taking into account theoretical and experimental constraints on the model, it turns out this type of signals - mostly uncovered by current searches - could be sizeable. We focus on three benchmark scenarios, each of them predicting up to 4000 multiboson events with the LHC Run 2 collected luminosity. Anomaly-detection methods could uncover those signals, if present in data.
description: LaTeX 13 pages. Added several discussions, matches version published in EPJC
Resistively-detected NMR lineshapes in a quasi-one dimensional electron system
Creators: name: Fauzi, M. H.
name: Singha, A.
name: Sahdan, M. F.
name: Takahashi, M.
name: Sato, K.
name: Nagase, K.
name: Muralidharan, B.
name: Hirayama, Y.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We observe variation in the resistively-detected nuclear magnetic resonance (RDNMR) lineshapes in quantum Hall breakdown. The breakdown is locally occurred in a gate-defined quantum point contact (QPC) region. Of particular interest is the observation of a dispersive lineshape occured when the bulk 2D electron gas (2DEG) is set to $ν_{\rm{b}} = 2$ and the QPC filling factor to the vicinity of $ν_{\rm{QPC}} = 1$, strikingly resemble the dispersive lineshape observed on a 2D quantum Hall state. This previously unobserved lineshape in a QPC points to simultaneous occurrence of two hyperfine-mediated spin flip-flop processes within the QPC. Those events give rise to two different sets of nuclei polarized in the opposite direction and positioned at a separate region with different degree of electronic polarizations.
description: Accepted as a rapid communication in PRB
Deep Learning Architecture Based Approach For 2D-Simulation of Microwave Plasma Interaction
Creators: name: Desai, Mihir
name: Ghosh, Pratik
name: Kumar, Ahlad
name: Chaudhury, Bhaskar
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Machine Learning (cs.LG)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: This paper presents a convolutional neural network (CNN)-based deep learning model, inspired from UNet with series of encoder and decoder units with skip connections, for the simulation of microwave-plasma interaction. The microwave propagation characteristics in complex plasma medium pertaining to transmission, absorption and reflection primarily depends on the ratio of electromagnetic (EM) wave frequency and electron plasma frequency, and the plasma density profile. The scattering of a plane EM wave with fixed frequency (1 GHz) and amplitude incident on a plasma medium with different gaussian density profiles (in the range of $1\times 10^{17}-1\times 10^{22}{m^{-3}}$) have been considered. The training data associated with microwave-plasma interaction has been generated using 2D-FDTD (Finite Difference Time Domain) based simulations. The trained deep learning model is then used to reproduce the scattered electric field values for the 1GHz incident microwave on different plasma profiles with error margin of less than 2\%. We propose a complete deep learning (DL) based pipeline to train, validate and evaluate the model. We compare the results of the network, using various metrics like SSIM index, average percent error and mean square error, with the physical data obtained from well-established FDTD based EM solvers. To the best of our knowledge, this is the first effort towards exploring a DL based approach for the simulation of complex microwave plasma interaction. The deep learning technique proposed in this work is significantly fast as compared to the existing computational techniques, and can be used as a new, prospective and alternative computational approach for investigating microwave-plasma interaction in a real time scenario.
A counterexample to a strong variant of the Polynomial Freiman-Ruzsa conjecture in Euclidean space
Creators: name: Lovett, Shachar
name: Regev, Oded
Publisher: name: arXiv
Year: 2016
Subjects: subject: Number Theory (math.NT)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: The Polynomial Freiman-Ruzsa conjecture is one of the central open problems in additive combinatorics. If true, it would give tight quantitative bounds relating combinatorial and algebraic notions of approximate subgroups. In this note, we restrict our attention to subsets of Euclidean space. In this regime, the original conjecture considers approximate algebraic subgroups as the set of lattice points in a convex body. Green asked in 2007 whether this can be simplified to a generalized arithmetic progression, while not losing more than a polynomial factor in the underlying parameters. We give a negative answer to this question, based on a recent reverse Minkowski theorem combined with estimates for random lattices.
Effects of Urban Boundary Layer Turbulence on Firebrand Transport
Creators: name: Santos, Iago Dal-Ri dos
name: Yaghoobian, Neda
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: This study investigates the role of topography-induced turbulence, generated by an idealized urban region, in the transport of firebrands and risk of spotting. Flight dispersion, deposition, and smoldering state of tens of thousands of individual mass and size-changing firebrands were investigated in the atmospheric boundary layer turbulence, which was obtained using Large-eddy simulations. Firebrands were assumed to be smoldering spherical particles of Stokes numbers ranging from 30 to 175. Results indicate that the presence of urban topography significantly affects the firebrand flight behavior, landing distribution, and risk of spotting. Compared to a case with flat topography, horizontal dispersions of the smallest size firebrands were significantly enhanced when urban topography was presented, while the largest firebrands landed closer to each other and closer to the release point. Consequently, a notably different and more compact spotting risk map was achieved. Within the urban boundary layer turbulence, firebrands had shorter flight and smoldering times in comparison with the flat case. As a result, firebrands landed with larger temperatures, which contributed to a higher risk of spotting in the presence of urban topography.
Commutator Subgroups of Welded Braid Groups
Creators: name: Dey, Soumya
name: Gongopadhyay, Krishnendu
Publisher: name: arXiv
Year: 2017
Subjects: subject: Geometric Topology (math.GT)
subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 20F36 (Primary), 20F12 (Secondary)

description: Let $WB_n$ be the welded (or loop) braid group on n strands, $n \geq 3$. We investigate commutator subgroup of $WB_n$. We prove that the commutator subgroup $WB_n'$ is finitely generated and Hopfian. We show that $WB_n'$ is perfect if and only if $n \geq 5$. We also compute finite presentation for $FWB_n'$, the commutator subgroup of the flat welded braid group $FWB_n$. Along the way, we investigate adorability of these groups.
description: 15 pages, introduction modified, notations changed, proofs restructured, minor corrections
Mixed Higgs-Radion States at the LHC -- a Detailed Study
Creators: name: Chakraborty, Amit
name: Maitra, Ushoshi
name: Raychaudhuri, Sreerup
name: Samui, Tousik
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Light radions constitute one of the few surviving possibilities for observable new particle states at the sub-TeV level which arise in models with extra spacetime dimensions. It is already known that the 125 GeV state discovered at CERN is unlikely to be a pure radion state, since its decays resemble those of the Standard Model Higgs boson too closely. However, due to experimental errors in the measured decay widths, the possibility still remains that it could be a mixture of the radion with one (or more) Higgs states. We use the existing LHC data at 8 and 13 TeV to make a thorough investigation of this possibility. Not surprisingly, it turns out that this model is already constrained quite effectively by direct LHC searches for an additional scalar heavier than 125 GeV. We then make a detailed study of the so-called 'conformal point', where this heavy state practically decouples from (most of) the Standard Model fields. Some projections for the future are also included.
description: Final version, to appear in Nuclear Physics B
Elliptic modular double and 4d partition functions
Creators: name: Lodin, Rebecca
name: Nieri, Fabrizio
name: Zabzine, Maxim
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Quantum Algebra (math.QA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We consider 4d supersymmetric (special) unitary $Γ$ quiver gauge theories on compact manifolds which are $T^2$ fibrations over $S^2$. We show that their partition functions are correlators of vertex operators and screening charges of the modular double version of elliptic $W_{q,t;q'}(Γ)$ algebras. We also consider a generating function of BPS surface defects supported on $T^2$ and show that it can be identified with a particular coherent state in the Fock module over the elliptic Heisenberg algebra.
description: v1: 34 pages, 3 figures; v2: corrected few typos, references added
H$α$-X-ray Surface Brightness Correlation for Filaments in Cooling Flow Clusters
Creators: name: Olivares, Valeria
name: Picquenot, Adrien
name: Su, Yuanyuan
name: Gaspari, Massimo
name: Gendron-Marsolais, Marie-Lou
name: Polles, Fiorella L.
name: Nulsen, Paul
Publisher: name: arXiv
Year: 2025
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Massive galaxies in cooling flow clusters display clear evidence of feedback from Active Galactic Nuclei (AGN). Joint X-ray and radio observations have shown that AGN radio jets push aside the surrounding hot gas and form cavities in the hot intracluster medium (ICM). These systems host complex, kiloparsec-scale, multiphase filamentary structures, from warm ionized (10,000 K) to cold molecular ($<$100 K). These striking clumpy filaments are believed to be a natural outcome of thermally unstable cooling from the hot ICM, likely triggered by feedback processes while contributing to feeding the AGN via Chaotic Cold Accretion (CCA). However, the detailed constraints on the formation mechanism of the filaments are still uncertain, and the connection between the different gas phases has to be fully unveiled. By leveraging a sample of seven X-ray bright cooling-flow clusters, we have discovered a tight positive correlation between the X-ray surface brightness and the H$α$ surface brightness of the filaments over two orders of magnitude, as also found in stripped tails.
description: Accepted for publication in Nature Astronomy, 32 pages, 10 figures
GPU-Accelerated Approximate Kernel Method for Quantum Machine Learning
Creators: name: Browning, Nicholas J.
name: Faber, Felix A.
name: von Lilienfeld, O. Anatole
Publisher: name: arXiv
Year: 2022
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Conventional kernel-based machine learning models for ab initio potential energy surfaces, while accurate and convenient in small data regimes, suffer immense computational cost as training set sizes increase. We introduce QML-Lightning, a PyTorch package containing GPU-accelerated approximate kernel models, which reduces the training time by several orders of magnitude, yielding trained models within seconds. QML-Lightning includes a cost-efficient GPU implementation of FCHL19, which together can yield energy and force predictions with competitive accuracy on a microsecond-per-atom timescale. Using modern GPU hardware, we report learning curves of energies and forces as well as timings as numerical evidence for select legacy benchmarks from atomisitic simulation including QM9, MD-17, and 3BPA.
description: 25 pages, 5 figures
Approximation by convolutions with probability densities and applications to PDEs
Creators: name: Gal, Sorin G.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: 41A35, 42A38, 44A35

description: The purpose of this paper is to introduce several new convolution operators, generated by some known probability densities. By using the inverse Fourier transform and taking inverse steps (in the analogues of the classical procedures used for, e.g., the heat or Laplace equations), we deduce the initial and final value problems satisfied by the new convolution integrals.
description: 11 pages, "TO PDEs" added to the title, Section 4 deleted, some changes made in Definition 2.1, (iv) and (v) and in Theorem 3.1, (iv) and (v)
Variational Approach to Quantum State Tomography based on Maximal Entropy Formalism
Creators: name: Gupta, Rishabh
name: Sajjan, Manas
name: Levine, Raphael D.
name: Kais, Sabre
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum state tomography is an integral part of quantum computation and offers the starting point for the validation of various quantum devices. One of the central tasks in the field of state tomography is to reconstruct with high fidelity, the quantum states of a quantum system. From an experiment on a real quantum device, one can obtain the mean measurement values of different operators. With such a data as input, in this report we employ the maximal entropy formalism to construct the least biased mixed quantum state that is consistent with the given set of expectation values. Even though in principle, the reported formalism is quite general and should work for an arbitrary set of observables, in practice we shall demonstrate the efficacy of the algorithm on an informationally complete (IC) set of Hermitian operators. Such a set possesses the advantage of uniquely specifying a single quantum state from which the experimental measurements have been sampled and hence renders the rare opportunity to not only construct a least-biased quantum state but even replicate the exact state prepared experimentally within a preset tolerance. The primary workhorse of the algorithm is re-constructing an energy function which we designate as the effective Hamiltonian of the system, and parameterizing it with Lagrange multipliers, according to the formalism of maximal entropy. These parameters are thereafter optimized variationally so that the reconstructed quantum state of the system converges to the true quantum state within an error threshold. To this end, we employ a parameterized quantum circuit and a hybrid quantum-classical variational algorithm to obtain such a target state making our recipe easily implementable on a near-term quantum device.
description: 18 pages, 5 figures
Predicted high-temperature superconductivity in rare earth hydride ErH2 at moderate pressure
Creators: name: Liu, Yiding
name: Fan, Qiang
name: Yang, Jianhui
name: Wang, Lili
name: Zhang, Weibin
name: Yao, Gang
Publisher: name: arXiv
Year: 2022
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Hydrides offer an opportunity to study high-temperature (Tc) superconductivity at experimentally achievable pressures. However, they remained extremely high. Using density functional theory calculations, herein we demonstrated that a newly rare earth hydride, namely bulk ErH2, could be superconducting with a Tc around 80 K at 14.5 GPa. To date, the drived pressure is the lowest reported value for compressed hydrides. Besides superconductivity, Fermi Surface nesting and Kondo effect were manifested at this pressure. Intriguingly, due to Kondo destruction, superconductivity was prone to exist at 15 GPa. Under the rest of applied pressures, we also revealed a gap of band structure at 20 GPa on the background of normal metallic states. At 20 GPa, this compressed system could act as a host of superconductor being judged from a sharp jump of spontaneous magnetic susceptibility with an evanescent spin density of state at Fermi level along with the competition between spin density wave and superconductivity. Finally, electron pairing glue for ErH2 at these three typical pressures was attributed to the antiferromagnetic spin fluctuation.
All-optical generation of deterministic squeezed Schrödinger-cat states
Creators: name: Zhang, Zhucheng
name: Shao, Lei
name: Lu, Wangjun
name: Wang, Xiaoguang
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum states are important resources and their preparations are essential prerequisites to all quantum technologies. However, they are extremely fragile due to the inevitable dissipations. Here, an all-optical generation of a deterministic squeezed Schr$\ddot{\mathrm{o}}$dinger-cat state based on dissipation is proposed. Our system is based on the Fredkin-type interaction between three optical modes, one of which is subject to coherent two-photon driving and the rest are coherent driving. We show that an effective degenerate three-wave mixing process can be engineered in our system, which can cause the simultaneous loss of two photons, resulting in the generation of a deterministic squeezed Schr$\ddot{\mathrm{o}}$dinger-cat state. More importantly, by controlling the driving fields in our system, the two-photon loss can be adjustable, which can accelerate the generation of squeezed Schr$\ddot{\mathrm{o}}$dinger-cat states. Besides, we exploit the squeezed Schr$\ddot{\mathrm{o}}$dinger-cat states to estimate the phase in the optical interferometer, and show that the quantum Fisher information about the phase can reach the Heisenberg limit in the limit of a large photon number. Meanwhile, it can have an order of magnitude factor improvement over the Heisenberg limit in the low-photon-number regime, which is very valuable for fragile systems that cannot withstand large photon fluxes. This work proposes an all-optical scheme to deterministically prepare the squeezed Schr$\ddot{\mathrm{o}}$dinger-cat state with high speed and can also be generalized to other physical platforms.
description: 12 pages, 6 figures
Did the Milky Way just light up? The recent star formation history of the Galactic disc
Creators: name: Zari, E.
name: Frankel, N.
name: Rix, H. -W.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: [Abridged] We map the stellar age distribution ($\lesssim 1$ Gyr) across a 6kpc$\,\times\,$6kpc area of the Galactic disc to constrain our Galaxy's recent star-formation history. Our modelling draws on the sample of Zari et al. (2021) that encompasses all presumed disc OBA stars ($\sim 500,000$ sources) with $G<16$. To be less sensitive to reddening, we do not forward model the detailed CMD distribution of these stars, but instead the K-band absolute magnitude distribution, $n(M_K)$, among stars with $M_K<0$ and $T_{\mathrm{eff}} > 7000$K at a certain positions $\vec{x}$ in the disc as a step function with five age bins, $b(τ~|~\vec{x}, \vecα)$, logarithmically-spaced in age from $τ= 5$ Myr to $τ= 1$ Gyr. Given a set of isochrones and a Kroupa (2001) initial mass function, we sample $b(τ\,|\,\vec{x}, \vecα)$ to maximize the likelihood of the data, accounting for the selection function. This results in a set of mono-age stellar density maps across a sizeable portion of the Galactic disc. These maps show that some, but not all, spiral arms are reflected in overdensities of stars younger than 500 Myr. The maps of the youngest stars ($<10$ Myr) trace major star forming regions. The maps at all ages exhibit an outward density gradient and distinct spiral-like spatial structure, which is qualitatively similar on large scales among all age intervals. When summing over the maps' area and extrapolating to the whole disc, we find an effective star-formation rate over the last 10 Myr of $\approx 3.3 \mathrm{M_{\odot}/yr}$, higher than previously published estimates. Remarkably, our stellar age distribution implies that the star-formation rate has been three times lower throughout most of the last Gyr, having risen distinctly only in the very recent past.
description: 11 pages, 9 figures. Submitted to A&A: comments welcome
Crosstalk Suppression in Individually Addressed Two-Qubit Gates in a Trapped-Ion Quantum Computer
Creators: name: Fang, Chao
name: Wang, Ye
name: Huang, Shilin
name: Brown, Kenneth R.
name: Kim, Jungsang
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Crosstalk between target and neighboring spectator qubits due to spillover of control signals represents a major error source limiting the fidelity of two-qubit entangling gates in quantum computers. We show that in our laser-driven trapped-ion system coherent crosstalk error can be modelled as residual $X\hatσ_ϕ$ interaction and can be actively cancelled by single-qubit echoing pulses. We propose and demonstrate a crosstalk suppression scheme that eliminates all first-order crosstalk, yet only requires local control by driving rotations solely on the target qubits. We report a two-qubit Bell state fidelity of $99.52(6) \%$ with the echoing pulses applied after collective gates and $99.37(5) \%$ with the echoing pulses applied to each gate in a 5-ion chain. This scheme is widely applicable to other platforms with analogous interaction Hamiltonians.
description: 9 pages, 4 figures