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Performance limits due to thermal transport in graphene single-photon bolometers

Physical Review Applied 2024年第1期21卷 014006-014006页

作者： Caleb Fried B. Jordan Russell Ethan G. Arnault Bevin Huang Gil-Ho Lee Dirk Englund Erik A. Henriksen Kin Chung Fong Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge Massachusetts 02139 Department of Earth and Planetary Sciences Harvard University Cambridge Massachusetts 02138 USA Department of Physics Harvard University Cambridge Massachusetts 02138 USA Raytheon BBN Quantum Engineering and Computing Group Cambridge Massachusetts 02138 USA Department of Physics Washington University in St. Louis St. Louis Missouri USA Intelligence Community Postdoctoral Research Fellowship Program Massachusetts Institute of Technology Cambridge Massachusetts 02139 Department of Physics Pohang University of Science and Technology Pohang 790-784 Republic of Korea

In high-sensitivity bolometers and calorimeters, the photon absorption often occurs at a finite distance from the temperature sensor to accommodate antennas or avoid the degradation of superconducting circuitry exposed to radiation. As a result, thermal propagation from the input to the temperature readout can critically affect detector performance. In this paper we model the performance of a graphene bolometer, accounting for electronic thermal diffusion and dissipation via electron-phonon coupling at low temperatures in three regimes: clean, supercollision, and resonant scattering. Our results affirm the feasibility of a superconducting readout without Cooper-pair breaking by mid- and near-infrared photons, and provide a recipe for designing graphene absorbers for calorimetric single-photon detectors. We investigate the trade-off between the input-readout distance and detector efficiency, and predict an intrinsic timing jitter of approximately 2.7 ps. Based on our result, we propose a spatial-mode-resolving photon detector to increase the communication bandwidth.

关键词： Heat transfer Metrology Optical quantum information processing Graphene Josephson junctions Bolometers Calorimetry Single-photon detectors

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Quasiparticle Poisoning of Superconducting Qubits from Resonant Absorption of Pair-breaking Photons

arXiv

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arXiv 2022年

作者： Liu, Chuan-Hong Harrison, D.C. Patel, S. Wilen, C.D. Rafferty, O. Shearrow, A. Ballard, A. Iaia, V. Ku, J. Plourde, B.L.T. McDermott, R. Department of Physics University of Wisconsin-Madison MadisonWI53706 United States Intelligence Community Postdoctoral Research Fellowship Program Department of Physics University of Wisconsin-Madison MadisonWI53706 United States Department of Physics Syracuse University SyracuseNY13244 United States

The ideal superconductor provides a pristine environment for the delicate states of a quantum computer: because there is an energy gap to excitations, there are no spurious modes with which the qubits can interact, causing irreversible decay of the quantum state. As a practical matter, however, there exists a high density of excitations out of the superconducting ground state even at ultralow temperature;these are known as quasiparticles. Observed quasiparticle densities are of order 1 µm−3, tens of orders of magnitude larger than the equilibrium density expected from theory. Nonequilibrium quasiparticles extract energy from the qubit mode and induce discrete changes in qubit offset charge, a potential source of dephasing. Here we show that a dominant mechanism for quasiparticle poisoning in superconducting qubits is direct absorption of high-energy photons at the qubit junction. We use a Josephson junction-based photon source to controllably dose qubit circuits with millimeter-wave radiation, and we use an interferometric quantum gate sequence to reconstruct the charge parity on the qubit island. We find that the structure of the qubit itself acts as a resonant antenna for millimeter-wave radiation, providing an efficient path for photons to generate quasiparticle excitations. A deep understanding of this physics will pave the way to realization of next-generation superconducting qubits that are robust against quasiparticle poisoning and could enable a new class of quantum sensors for dark matter detection. Copyright © 2022, The Authors. All rights reserved.

关键词： Photons

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Some Entanglement Survives Most Measurements

arXiv

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arXiv 2023年

作者： Gonzales, Alvin Dilley, Daniel Byrd, Mark Intelligence Community Postdoctoral Research Fellowship Program Argonne National Laboratory 9700 S. Cass Avenue LemontIL60439 United States School of Computing Southern Illinois University Carbondale CarbondaleIL62901 United States School of Physics and Applied Physics Southern Illinois University Carbondale CarbondaleIL62901 United States

To prepare quantum states and extract information, it is often assumed that one can perform a perfectly projective measurement. Such measurements can achieve an uncorrelated system and environment state. However, perfectly projective measurements can be difficult or impossible to perform in practice. We investigate the limitations of repeated non-projective measurements in preparing a quantum system. For an n-qubit system initially entangled with its environment and subsequently prepared with measurements, using a sequence of weak measurements, we show that some entanglement remains unless one of the measurement operators becomes perfectly projective through an extreme limiting process. Removing initial (unentangled) correlations between a system and its environment and the scenario where measurement outcomes are not tracked are also discussed. We present results for n-qubit and n-dimensional input states. Copyright © 2023, The Authors. All rights reserved.

关键词： Quantum entanglement

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Fault Tolerant Quantum Error Mitigation

arXiv

引用

arXiv 2023年

作者： Gonzales, Alvin Babu, Anjala M. Liu, Ji Saleem, Zain Byrd, Mark Intelligence Community Postdoctoral Research Fellowship Program Argonne National Laboratory LemontIL United States School of Physics and Applied Physics Southern Illinois University CarbondaleIL United States Mathematics and Computer Science Division Argonne National Laboratory LemontIL United States School of Computing Southern Illinois University CarbondaleIL United States

Typically, fault-tolerant operations and code concatenation are reserved for quantum error correction due to their resource overhead. Here, we show that fault tolerant operations have a large impact on the performance of symmetry based error mitigation techniques. We also demonstrate that similar to results in fault tolerant quantum computing, code concatenation in fault-tolerant quantum error mitigation (FTQEM) can exponentially suppress the errors to arbitrary levels. For a family of circuits, we provide analytical error thresholds for FTQEM with the repetition code. These circuits include a set of quantum circuits that can generate all of reversible classical computing. The post-selection rate in FTQEM can also be increased by correcting some of the outcomes. Our threshold results can also be viewed from the perspective of quantifying the number of gate operations we can delay checking the stabilizers in a concatenated code before errors overwhelm the encoding. The benefits of FTQEM are demonstrated with numerical simulations and hardware demonstrations. Copyright © 2023, The Authors. All rights reserved.

关键词： Quantum computers

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S8 Tension in the Context of Dark Matter-Baryon Scattering

arXiv

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arXiv 2023年

作者： He, Adam Ivanov, Mikhail M. An, Rui Gluscevic, Vera Department of Physics and Astronomy University of Southern California Los AngelesCA90089 United States School of Natural Sciences Institute for Advanced Study 1 Einstein Drive PrincetonNJ08540 United States NASA Hubble Fellowship Program Einstein Postdoctoral Fellow United States Center for Theoretical Physics Massachusetts Institute of Technology CambridgeMA02139 United States

We explore an interacting dark matter (IDM) model that allows for a fraction of dark matter (DM) to undergo velocity-independent scattering with baryons. In this scenario, structure on small scales is suppressed relative to the cold DM scenario. Using the effective field theory of large-scale structure, we perform the first systematic analysis of BOSS full-shape galaxy clustering data for the IDM scenario, and we find that this model ameliorates the S8 tension between large-scale structure and Planck data. Adding the S8 prior from DES to our analysis further leads to a mild ∼ 3σ preference for a non-vanishing DM-baryon scattering cross-section, assuming ∼ 10% of DM is interacting and has a particle mass of 1 MeV. This result produces a modest ∼ 20% suppression of the linear power at k 1 h/Mpc, consistent with other small-scale structure observations. Similar scale-dependent power suppression was previously shown to have the potential to resolve S8 tension between cosmological data sets. The validity of the specific IDM model explored here will be critically tested with upcoming galaxy surveys at the interaction level needed to alleviate the S8 tension. Copyright © 2023, The Authors. All rights reserved.

关键词： Galaxies

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Dual-Element, Two-Dimensional Atom Array with Continuous-Mode Operation

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Physical Review X 2022年第1期12卷 011040-011040页

作者： Kevin Singh Shraddha Anand Andrew Pocklington Jordan T. Kemp Hannes Bernien Intelligence Community Postdoctoral Research Fellowship Program Pritzker School of Molecular Engineering University of Chicago Chicago Illinois 60637 USA Pritzker School of Molecular Engineering University of Chicago Chicago Illinois 60637 USA Department of Physics University of Chicago Chicago Illinois 60637 USA

Quantum processing architectures that include multiple qubit modalities offer compelling strategies for high-fidelity operations and readout, quantum error correction, and a path for scaling to large system sizes. Such hybrid architectures have been realized for leading platforms, including superconducting circuits and trapped ions. Recently, a new approach for constructing large, coherent quantum processors has emerged based on arrays of individually trapped neutral atoms. However, these demonstrations have been limited to arrays of a single atomic element where the identical nature of the atoms makes crosstalk-free control and nondemolition readout of a large number of atomic qubits challenging. Here we introduce a dual-element atom array with individual control of single rubidium and cesium atoms. We demonstrate their independent placement in arrays with up to 512 trapping sites and observe negligible crosstalk between the two elements. Furthermore, by continuously reloading one atomic element while maintaining an array of the other, we demonstrate a new continuous operation mode for atom arrays without any off-time. Our results enable avenues for auxiliary-qubit-assisted quantum protocols such as quantum nondemolition measurements and quantum error correction, as well as continuously operating quantum processors and sensors.

关键词： Hybrid quantum systems Quantum information architectures & platforms Atom & ion cooling Cooling & trapping Optical tweezers

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Primordial Stochastic Gravitational Wave Backgrounds from a Sharp Feature in Three-field Inflation II: The Inflationary Era

arXiv

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arXiv 2024年

作者： Aragam, Vikas Paban, Sonia Rosati, Robert Medical Physics Division Thomas Jefferson University PhiladelphiaPA19107 United States Jefferson Physical Laboratory Harvard University CambridgeMA02138 United States NASA Postdoctoral Program Fellow NASA Marshall Space Flight Center HuntsvilleAL35812 United States Department of Astronomy and Astrophysics University of California Santa CruzCA95064 United States

We study the contribution of large scalar perturbations sourced by a sharp feature during cosmic inflation to the stochastic gravitational wave background (SGWB), extending our previous work to include the SGWB sourced during the inflationary era. We focus in particular on three-field inflation, since the third dynamical field is the first not privileged by the perturbations’ equations of motion and allows a more direct generalization to N-field inflation. For the first time, we study the three-field isocurvature perturbations sourced during the feature and include the effects of isocurvature masses. In addition to a two-field limit, we find that the third field’s dynamics during the feature can source large isocurvature transients which then later decay, leaving an inflationary-era-sourced SGWB as their only observable signature. We find that the inflationary-era signal shape near the peak is largely independent of the number of dynamical fields and has a greatly enhanced amplitude sourced by the large isocurvature transient, suppressing the radiation-era contribution and opening a new window of detectable parameter space with small adiabatic enhancement. The largest enhancements we study could easily violate backreaction constraints, but much of parameter space remains under perturbative control. These SGWBs could be visible in LISA and other gravitational wave experiments, leaving an almost universal signature of sharp features during multi-field inflation, even when the sourcing isocurvature decays to unobservability shortly afterwards. © 2024, CC BY.

关键词： Gravity waves

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The Fermi-LAT Light Curve Repository: A resource for the time-domain and multi-messenger communities

arXiv

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arXiv 2023年

作者： Valverde, Janeth Kocevski, D. Negro, M. Garrappa, S. Brill, A. Department of Physics Center for Space Sciences and Technology University of Maryland Baltimore County BaltimoreMD21250 United States NASA Goddard Space Flight Center GreenbeltMD20771 United States NASA Marshall Space Flight Center HuntsvilleAL35812 United States Department of Physics & Astronomy Louisiana State University Baton RougeLA70803 United States Department of Particle Physics and Astrophysics Weizmann Institute of Science Rehovot76100 Israel NASA Postdoctoral Program United States

For over 15 years the Fermi Large Area Telescope (Fermi-LAT) has been monitoring the entire high-energy gamma-ray sky, providing the best sampled 0.1 - > 1 TeV photons to this day. As a result, the Fermi-LAT has been serving the time-domain and multi-messenger community as the main source of gamma-ray activity alerts. All of this makes the Fermi-LAT a key instrument towards understanding the underlying physics behind the most extreme objects in the universe. However, generating mission-long LAT light curves can be very computationally expensive. The Fermi-LAT light curve repository (LCR) tackles this issue. The LCR is a public library of gamma-ray light curves for 1525 Fermi-LAT sources deemed variable in the 4FGL-DR2 catalog. The repository consists of light curves on timescales of days, weeks, and months, generated through a full-likelihood unbinned analysis of the source and surrounding region, providing flux and photon index measurements for each time interval. Hosted at NASA's FSSC, the library provides users with access to this continually updated light curve data, further serving as a resource to the time-domain and multi-messenger communities. Copyright © 2023, The Authors. All rights reserved.

关键词： Gamma rays

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Oscillations in Gas-grain Astrochemical Kinetics

arXiv

引用

arXiv 2023年

作者： Dufour, Gwenaëlle Charnley, Steven B. Lindberg, Johan E. Astrochemistry Laboratory Code 691 NASA Goddard Space Flight Center GreenbeltMD20771 United States Department of Physics Catholic University of America WashingtonDC20064 United States Leiden Observatory Leiden University Leiden Netherlands NASA Postdoctoral Program NASA Goddard Space Flight Center Universities Space Research Association NASA United States

We have studied gas-grain chemical models of interstellar clouds to search for nonlinear dynamical evolution. A prescription is given for producing oscillatory solutions when a bistable solution exists in the gas-phase chemistry and we demonstrate the existence of limit cycle and relaxation oscillation solutions. As the autocatalytic chemical processes underlying these solutions are common to all models of interstellar chemistry, the occurrence of these solutions should be widespread. We briefly discuss the implications for interpreting molecular cloud composition with time-dependent models and some future directions for this approach. Copyright © 2023, The Authors. All rights reserved.

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Damping of long wavelength gravitational waves by the intergalactic medium

arXiv

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arXiv 2022年

作者： Lieu, Richard Lackeos, Kristen Zhang, Bing Department of Physics and Astronomy University of Alabama HuntsvilleAL35899 United States NASA Postdoctoral Program NASA Marshall Space Flight Center HuntsvilleAL35812 United States Auf dem Hügel 69 Bonn53121 Germany Department of Physics and Astronomy University of Nevada Las VegasNV89154 United States

The problem of radiation by the charged particles of the intergalactic medium (IGM) when a passing gravitational wave (GW) accelerate them is investigated. The largest acceleration (taking a charge from rest to a maximum speed which remains non-relativistic in the rest frame of the unperturbed spacetime) is found to be limited by the curvature of a propagating spherical gravitational wavefront. Interesting physics arises from the ensuing emission of radiation into the warm hot IGM, which to lowest order is a fully ionized hydrogen plasma with a frozen-in magnetic field B. It is found that for a vast majority of propagation directions, the right-handed polarized radiation can penetrate the plasma at frequencies below the plasma frequency ωp, provided ω b, where ωb = eB/me satisfies ωb p for typical IGM conditions. Moreover, the refractive index under such a scenario is n 1, resulting in an enhanced radiative dissipation of GW energy (relative to the vacuum scenario), which is more severe for electrons if both charge species are in thermal equilibrium and accelerated in the same way. The emission by the electrons then prevails, and is further amplified by coherent addition of amplitudes within the size one wavelength. The conversion of GWs of λ 5 × 1013 cm to electromagnetic waves means such GWs can only propagate a distance 1 Gpc before being significantly damped by an IGM B field of ∼ 10−8 G. The low-frequency GWs targeted by pulsar-timing-arrays will not survive unless the IGM magnetic field is much lower than expected. The mHz frequency GW inspirals targeted by future space based detectors such as the Laser Interferometer Space Antenna remain intact and can be detected. © 2022, CC BY.

关键词： Interferometers

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