Physical Review Applied最新文献

{"title":"Resonant switching current detector based on underdamped Josephson junctions","authors":"Vladimir M. Krasnov","doi":"10.1103/physrevapplied.22.024015","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024015","url":null,"abstract":"Current-biased Josephson junctions can act as detectors of electromagnetic radiation. At optimal conditions, their sensitivity is limited by fluctuations causing stochastic switching from the superconducting to the resistive state. This work provides a quantitative description of a stochastic switching current detector, based on an underdamped Josephson junction. It is shown that activation of a Josephson plasma resonance can greatly enhance the detector responsivity in proportion to the quality factor of the junction. The ways of tuning the detector for achieving optimal operation are discussed. For realistic parameters of <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Nb</mi></math>/<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mrow><mi>Al</mi><mi mathvariant=\"normal\">O</mi></mrow><mi>x</mi></msub></math>/<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Nb</mi></math> tunnel junctions, the sensitivity and noise-equivalent power (NEP) can reach values of <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>S</mi><mo>≃</mo><mspace width=\"0.2em\"></mspace><mn>5</mn><mo>×</mo><msup><mn>10</mn><mn>12</mn></msup></math> (V/W) and <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>NEP</mi><mo>≃</mo><mspace width=\"0.2em\"></mspace><mn>2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>23</mn></mrow></msup></math> (<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>WHz</mi><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math>), respectively. These outstanding characteristics facilitate both bolometric and single-photon detection in microwave and terahertz ranges.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"5 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photochemically induced acousto-optics in gases","authors":"P. Michel, L. Lancia, A. Oudin, E. Kur, C. Riconda, K. Ou, V.M. Perez-Ramirez, J. Lee, M.R. Edwards","doi":"10.1103/physrevapplied.22.024014","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024014","url":null,"abstract":"Acousto-optics consists of launching acoustic waves in a medium (usually a crystal) in order to modulate its refractive index and create a tunable optical grating. In this article, we present the theoretical basis of an alternative scheme to generate acousto-optics in a gas, where the acoustic waves are initiated by the localized absorption (and thus gas heating) of spatially modulated UV light, as was demonstrated by Michine and Yoneda [Commun. Phys. 3, 24 (2020)]. We identify the chemical reactions initiated by the absorption of UV light via the photodissociation of ozone molecules present in the gas, and calculate the resulting temperature increase in the gas as a function of space and time. Solving the Euler fluid equations shows that the modulated, isochoric heating initiates a mixed acoustic-entropy wave in the gas, whose high-amplitude density (and thus refractive index) modulation can be used to manipulate a high-power laser. We calculate that diffraction efficiencies near 100% can be obtained using only a few millimeters of gas containing a few percent ozone fraction at room temperature, with UV fluences of less than 100 <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mrow><mrow><mi>mJ</mi><mo>/</mo><mi>cm</mi></mrow></mrow><mn>2</mn></msup></math>—consistent with the experimental measurements. Our analysis suggests possible ways to optimize the diffraction efficiency by changing the buffer gas composition. Gases have optics damage thresholds 2–3 orders of magnitude beyond those of solids; these optical elements should therefore be able to manipulate kilojoule-class lasers.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"15 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pulse-based variational quantum optimization and metalearning in superconducting circuits","authors":"Yapeng Wang, Yongcheng Ding, Francisco Andrés Cárdenas-López, Xi Chen","doi":"10.1103/physrevapplied.22.024009","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024009","url":null,"abstract":"Solving optimization problems using variational algorithms stands out as a crucial application for noisy intermediate-scale devices. Instead of constructing gate-based quantum computers, our focus centers on designing variational quantum algorithms within the analog paradigm. This involves optimizing parameters that directly control pulses, driving quantum states toward target states without the necessity to compile a quantum circuit. In this work, we introduce pulse-based variational quantum optimization (PBVQO) as a hardware-level framework. We illustrate the framework by optimizing external fluxes on superconducting quantum interference devices, effectively driving the wave function of this specific quantum architecture to the ground state of an encoded problem Hamiltonian. Given that the performance of variational algorithms relies heavily on appropriate initial parameters, we introduce a global optimizer as a metalearning technique to tackle a simple problem. The synergy between PBVQO and metalearning provides an advantage over conventional gate-based variational algorithms.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"32 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced measurement of neutral-atom qubits with machine learning","authors":"L. Phuttitarn, B. M. Becker, R. Chinnarasu, T. M. Graham, M. Saffman","doi":"10.1103/physrevapplied.22.024011","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024011","url":null,"abstract":"We demonstrate qubit-state measurements assisted by a supervised convolutional neural network (CNN) in a neutral-atom quantum processor. We present two CNN architectures for analyzing neutral-atom qubit readout data: a compact five-layer single-qubit CNN architecture and a six-layer multiqubit CNN architecture. We benchmark both architectures against a conventional Gaussian-threshold analysis method. In a sparse array (9-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mtext fontfamily=\"times\">μ</mtext><mrow><mi mathvariant=\"normal\">m</mi></mrow></math> atom separation) which experiences negligible crosstalk, we have observed up to 32% and 56% error reduction for the multiqubit and single-qubit architectures, respectively, as compared to the benchmark. In a tightly spaced array (5-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mtext fontfamily=\"times\">μ</mtext><mrow><mi mathvariant=\"normal\">m</mi></mrow></math> atom separation), which suffers from readout crosstalk, we have observed up to 43% and 32% error reduction in the multiqubit and single-qubit CNN architectures, respectively, as compared to the benchmark. By examining the correlation between the predicted states of neighboring qubits, we have found that the multiqubit CNN architecture reduces the crosstalk correlation by up to 78.5%. This work demonstrates a proof of concept for a CNN network to be implemented as a real-time readout-processing method on a neutral-atom quantum computer, enabling faster readout time and improved fidelity.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"5 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"All-electrical cooling of an optically levitated nanoparticle","authors":"Oscar Kremer, Igor Califrer, Daniel Tandeitnik, Jean Pierre von der Weid, Guilherme Temporão, Thiago Guerreiro","doi":"10.1103/physrevapplied.22.024010","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024010","url":null,"abstract":"We implement an all-electrical controller for 3D feedback cooling of an optically levitated nanoparticle capable of reaching subkelvin temperatures for the center-of-mass motion. The controller is based on an optimal policy in which state estimation is made by delayed position measurements. The method offers a simplified path for precooling and decoupling the transverse degrees of freedom of the nanoparticle. Numerical simulations show that in an improved setup with quantum limited detection, all three axes can be cooled down to a few-phonon regime.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"41 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing the hyperbolic bandwidth in two-dimensional materials via atomic orbital engineering","authors":"Shuting Hou, Xikui Ma, Chao Ding, Yueheng Du, Mingwen Zhao","doi":"10.1103/physrevapplied.22.024005","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024005","url":null,"abstract":"The emergence of two-dimensional (2D) hyperbolic materials, characterized by opposite-sign optical conductivities along two orthogonal axes within a specific band (known as the hyperbolic region), opens an avenue for optical device engineering. Broadening the hyperbolic region is essential for cutting-edge photonic applications. In this study, based on a correlation between the hyperbolic region and anisotropic electronic structures, we propose a strategic framework for identifying 2D natural hyperbolic materials (NHMs) with broadband hyperbolicity. Using this framework, we engineered a 2D lattice incorporating <i>p</i> and <i>d</i> orbitals, and discovered a series of 2D NHMs, <i>MYZ</i> (<i>M</i> = <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Co</mi><mo>,</mo><mspace width=\"0.2em\"></mspace><mi>Pd</mi><mo>,</mo><mspace width=\"0.2em\"></mspace><mi>Ru</mi><mo>,</mo><mspace width=\"0.2em\"></mspace><mi>Rh</mi></math>; <i>Y</i> = <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mrow><mi mathvariant=\"normal\">S</mi></mrow></mrow><mo>,</mo><mspace width=\"0.2em\"></mspace><mi>Se</mi><mo>,</mo><mspace width=\"0.2em\"></mspace><mi>Te</mi></math>; and <i>Z</i> = <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Cl</mi><mo>,</mo><mspace width=\"0.2em\"></mspace><mi>Br</mi><mo>,</mo><mspace width=\"0.2em\"></mspace><mrow><mrow><mi mathvariant=\"normal\">I</mi></mrow></mrow></math>). These materials exhibit broadband hyperbolicity that extends from the near-infrared to the visible-light spectrum. We have confirmed the directional propagation of surface plasmon polaritons on these 2D materials based on Maxwell’s equations. Our findings pave the way for future exploration and practical deployment of 2D NHMs in advanced technological applications.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"46 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141883909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Terahertz dynamic multiband perfect absorber with a digital coding graphene-diamond metasurface","authors":"Shaowei Zhang, Feng Wen, Muhua Zhai, Zheng Li, Huapeng Ye, Hengxi Zhang, Yangxin Gu, Yang Lei, Wei Wang, Yanpeng Zhang, Hongxing Wang","doi":"10.1103/physrevapplied.22.024004","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024004","url":null,"abstract":"The monolayer graphene-based terahertz (THz) perfect absorber has made significant progress in switchable devices with diverse functionalities. However, existing methods for achieving switchability rely on either multilayered metasurface with complex configurations or complicated patterned metasurfaces. A switchable absorber that switches between <i>n</i>-band and <i>m</i>-band modes (<i>n</i>, <i>m</i> correspond to the number of resonance peaks) using tunable materials is also interesting but has not yet been mentioned. Here, a dynamically switchable multiband perfect absorber with a digital coding graphene metasurface is proposed and demonstrated. By integrating multiple metasurface units with different Fermi levels into a newly generated period, we realize a multiband perfect absorber with a rather simple and straightforward configuration composed of a patterned metasurface. Through introducing a digital coding metasurface into the perfect absorber, we use the digital signals via FPGA (field programmable gate array) to convert <i>n</i>-band into <i>m</i>-band absorption modes. Moreover, the results reveal that the THz perfect absorber, possessing great impedance matching with the free space, has excellent angle tolerance and robustness. Such a perfect absorber offers a flexible tool for selecting THz channels and may pave the way for <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>sixth</mi><mo>−</mo></msup></math>generation communication.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"37 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141883612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exceptional points in transistor-metamaterial-inspired transmission lines","authors":"David E. Fernandes, Sylvain Lannebère, Tiago A. Morgado, Mário G. Silveirinha","doi":"10.1103/physrevapplied.22.024003","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024003","url":null,"abstract":"Motivated by our recent findings in [Phys. Rev. Lett. 128, 013902, 2022], which introduced a new class of electromagnetic bulk materials whose response is similar to conventional semiconductor transistors, here we propose a one-dimensional (1D) version of such materials based on transmission lines coupled with FET isolators. We demonstrate that the response of this 1D system is nonreciprocal and non-Hermitian, analogous to the idealized transistor-metamaterial, and is also characterized by a broken time-reversal symmetry. We analyze the wave propagation in the system and find that the interaction between the eigenmodes can either lead to gain or loss, depending on the propagation distance. Furthermore, it is also shown that the system may be operated at an exceptional point, wherein the response becomes singular, and the power gain is maximized. Finally, we demonstrate that the exceptional point coincides with the point of operation of typical microwave amplifiers, such as the distributed amplifier.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"298 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141883613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Na2KSb/CsxSb interface engineering for high-efficiency photocathodes","authors":"S.A. Rozhkov, V.V. Bakin, V.S. Rusetsky, D.A. Kustov, V.A. Golyashov, A.Yu. Demin, H.E. Scheibler, V.L. Alperovich, O.E. Tereshchenko","doi":"10.1103/physrevapplied.22.024008","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024008","url":null,"abstract":"Optical and photoemission measurements were performed on alkali antimonide &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;msub&gt;&lt;mi&gt;Na&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mi&gt;KSb&lt;/mi&gt;&lt;/math&gt; and &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;msub&gt;&lt;mi&gt;Na&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mi&gt;KSb&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;Cs&lt;/mi&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/msub&gt;&lt;mi&gt;Sb&lt;/mi&gt;&lt;/math&gt; photocathodes in order to determine their energy-band diagrams, elucidate the photoemission pathways, and explore the options for interface engineering in order to reach high quantum efficiencies of the photocathodes. This study is motivated by the recent discovery of optical orientation in &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;msub&gt;&lt;mi&gt;Na&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mi&gt;KSb&lt;/mi&gt;&lt;/math&gt; and emission of spin-polarized electrons from &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;msub&gt;&lt;mi&gt;Na&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mi&gt;KSb&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;Cs&lt;/mi&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/msub&gt;&lt;mi&gt;Sb&lt;/mi&gt;&lt;/math&gt; photocathodes [V.S. Rusetsky &lt;i&gt;et al.&lt;/i&gt;, Phys. Rev. Lett. &lt;b&gt;129&lt;/b&gt;, 166802 (2022)]. We have shown that the band gap &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;msub&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/msub&gt;&lt;/math&gt; of &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;msub&gt;&lt;mi&gt;Na&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mi&gt;KSb&lt;/mi&gt;&lt;/math&gt; at &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;295&lt;/mn&gt;&lt;/math&gt; K lies within the range of 1.40–1.44 eV. The &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;msub&gt;&lt;mi&gt;Na&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mi&gt;KSb&lt;/mi&gt;&lt;/math&gt; surface activation by the deposition of &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mi&gt;Cs&lt;/mi&gt;&lt;/math&gt; and &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mi&gt;Sb&lt;/mi&gt;&lt;/math&gt; results in effective electron affinity decrease by approximately 0.37 eV, and in an increase of the quantum efficiency up to 0.2 electrons per incident photon. The analysis of longitudinal energy distribution curves (EDCs) proves that the surface of activated &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;msub&gt;&lt;mi&gt;Na&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mi&gt;KSb&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;Cs&lt;/mi&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/msub&gt;&lt;mi&gt;Sb&lt;/mi&gt;&lt;/math&gt; photocathodes have negative effective electron affinity of approximately &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0.1&lt;/mn&gt;&lt;/math&gt; and &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0.25&lt;/mn&gt;&lt;/math&gt; eV at &lt;math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;295&lt;/mn&gt;&lt;/math&gt; and 80 K, respectively. EDC measurements under increasing photon energy &lt;math display","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"190 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141883609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced quantum state transfer and Bell-state generation over long-range multimode interconnects via superadiabatic transitionless driving","authors":"Moein Malekakhlagh, Timothy Phung, Daniel Puzzuoli, Kentaro Heya, Neereja Sundaresan, Jason Orcutt","doi":"10.1103/physrevapplied.22.024006","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024006","url":null,"abstract":"Achieving high-fidelity direct two-qubit gates over meter-scale quantum interconnects is challenging, in part due to the multimode nature of such systems. One alternative scheme is to combine local operations with remote quantum state transfer or remote entanglement. Here, we theoretically study quantum state transfer and entanglement generation for two distant qubits, equipped with tunable interactions, over a common multimode interconnect. We model the performance of the superadiabatic transitionless driving (SATD) protocol for adiabatic passage and demonstrate various favorable improvements over the standard method. In particular, by suppressing leakage to a select (resonant) interconnect mode, SATD breaks the speed-limit relation imposed by the qubit-interconnect interaction <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>g</mi></math>, where instead the operation time is limited by leakage to the adjacent modes, i.e., the free spectral range <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi mathvariant=\"normal\">Δ</mi><mi>c</mi></msub></math> of the interconnect, allowing for fast operations even with weak <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>g</mi></math>. Furthermore, we identify a multimode error mechanism for Bell-state generation using such adiabatic protocols, in which the even/odd modal dependence of qubit-interconnect interaction breaks down the dark-state symmetry, leading to detrimental adiabatic overlap with the odd modes growing as <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo stretchy=\"false\">(</mo><mi>g</mi><mo>/</mo><msub><mi mathvariant=\"normal\">Δ</mi><mi>c</mi></msub><msup><mo stretchy=\"false\">)</mo><mn>2</mn></msup></math>. Therefore, adopting a weak coupling, imposed by a multimode interconnect, SATD provides a significant improvement in terms of operation speed and consequently sensitivity to incoherent error.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"46 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141883611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}