Pub Date : 2024-11-08DOI: 10.1103/physrevx.14.041039
C. Chen, Y. Liu, Y. Chen, Y. N. Hu, T. Z. Zhang, D. Li, X. Wang, C. X. Wang, Z. Y. W. Lu, Y. H. Zhang, Q. L. Zhang, X. L. Dong, R. Wang, D. L. Feng, T. Zhang
Vortex pinning is a crucial factor that determines the critical current of practical superconductors and enables their diverse applications. However, the underlying mechanism of vortex pinning has long been elusive, lacking a clear microscopic explanation. Here, using high-resolution scanning tunneling microscopy, we studied single vortex pinning induced by point defect in layered FeSe-based superconductors. We found the defect-vortex interaction drives low-energy vortex bound states away from 𝐸F, creating a “mini” gap that effectively lowers the system energy and enhances pinning. By measuring the local density of states, we directly obtained the elementary pinning energy and estimated the pinning force via the spatial gradient of pinning energy. The results are consistent with bulk critical current measurement. Furthermore, we showed that a general microscopic quantum model incorporating defect-vortex interaction can naturally capture our observation. It suggests that the local pairing near pinned vortex core is actually enhanced compared to unpinned vortex, which is beyond the traditional understanding that nonsuperconducting regions pin vortices. Our study thus unveils a general microscopic mechanism of vortex pinning in superconductors and provides insights for enhancing the critical current of practical superconductors.
{"title":"Revealing the Microscopic Mechanism of Elementary Vortex Pinning in Superconductors","authors":"C. Chen, Y. Liu, Y. Chen, Y. N. Hu, T. Z. Zhang, D. Li, X. Wang, C. X. Wang, Z. Y. W. Lu, Y. H. Zhang, Q. L. Zhang, X. L. Dong, R. Wang, D. L. Feng, T. Zhang","doi":"10.1103/physrevx.14.041039","DOIUrl":"https://doi.org/10.1103/physrevx.14.041039","url":null,"abstract":"Vortex pinning is a crucial factor that determines the critical current of practical superconductors and enables their diverse applications. However, the underlying mechanism of vortex pinning has long been elusive, lacking a clear microscopic explanation. Here, using high-resolution scanning tunneling microscopy, we studied single vortex pinning induced by point defect in layered FeSe-based superconductors. We found the defect-vortex interaction drives low-energy vortex bound states away from <mjx-container ctxtmenu_counter=\"342\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(2 0 1)\"><mjx-mrow><mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-owns=\"0 1\" data-semantic-role=\"latinletter\" data-semantic-speech=\"upper E Subscript normal upper F\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c>𝐸</mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em; margin-left: -0.016em;\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\" size=\"s\"><mjx-c>F</mjx-c></mjx-mi></mjx-script></mjx-msub></mjx-mrow></mjx-math></mjx-container>, creating a “mini” gap that effectively lowers the system energy and enhances pinning. By measuring the local density of states, we directly obtained the elementary pinning energy and estimated the pinning force via the spatial gradient of pinning energy. The results are consistent with bulk critical current measurement. Furthermore, we showed that a general microscopic quantum model incorporating defect-vortex interaction can naturally capture our observation. It suggests that the local pairing near pinned vortex core is actually enhanced compared to unpinned vortex, which is beyond the traditional understanding that nonsuperconducting regions pin vortices. Our study thus unveils a general microscopic mechanism of vortex pinning in superconductors and provides insights for enhancing the critical current of practical superconductors.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"196 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Pub Date : 2024-11-08DOI: 10.1103/physrevx.14.041038
Matthew P. Leighton, Jannik Ehrich, David A. Sivak
Heat engines and information engines have each historically served as motivating examples for the development of thermodynamics. While these two types of systems are typically thought of as two separate kinds of machines, recent empirical studies of specific systems have hinted at possible connections between the two. Inspired by molecular machines in the cellular environment, which in many cases have separate components in contact with distinct sources of fluctuations, we study bipartite heat engines. We show that a bipartite heat engine can produce net output work only by acting as an information engine. Conversely, information engines can extract more work than the work consumed to power them only if they have access to different sources of fluctuations, i.e., act as heat engines. We illustrate these findings first through an analogy to economics and a cyclically controlled 2D ideal gas. We then explore two analytically tractable model systems in more detail: a Brownian-gyrator heat engine, which we show can be reinterpreted as a feedback-cooling information engine, and a quantum-dot information engine, which can be reinterpreted as a thermoelectric heat engine. Our results suggest design principles for both heat engines and information engines at the nanoscale and ultimately imply constraints on how free-energy transduction is carried out in biological molecular machines.
{"title":"Information Arbitrage in Bipartite Heat Engines","authors":"Matthew P. Leighton, Jannik Ehrich, David A. Sivak","doi":"10.1103/physrevx.14.041038","DOIUrl":"https://doi.org/10.1103/physrevx.14.041038","url":null,"abstract":"Heat engines and information engines have each historically served as motivating examples for the development of thermodynamics. While these two types of systems are typically thought of as two separate kinds of machines, recent empirical studies of specific systems have hinted at possible connections between the two. Inspired by molecular machines in the cellular environment, which in many cases have separate components in contact with distinct sources of fluctuations, we study bipartite heat engines. We show that a bipartite heat engine can produce net output work only by acting as an information engine. Conversely, information engines can extract more work than the work consumed to power them only if they have access to different sources of fluctuations, i.e., act as heat engines. We illustrate these findings first through an analogy to economics and a cyclically controlled 2D ideal gas. We then explore two analytically tractable model systems in more detail: a Brownian-gyrator heat engine, which we show can be reinterpreted as a feedback-cooling information engine, and a quantum-dot information engine, which can be reinterpreted as a thermoelectric heat engine. Our results suggest design principles for both heat engines and information engines at the nanoscale and ultimately imply constraints on how free-energy transduction is carried out in biological molecular machines.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"18 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Pub Date : 2024-11-07DOI: 10.1103/physrevx.14.041036
Andreas Gleis, Seung-Sup B. Lee, Gabriel Kotliar, Jan von Delft
We study paramagnetic quantum criticality in the periodic Anderson model (PAM) using cellular dynamical mean-field theory (CDMFT), with the numerical renormalization group (NRG) as a cluster impurity solver. The PAM describes itinerant <mjx-container ctxtmenu_counter="273" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="0"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-role="latinletter" data-semantic-speech="c" data-semantic-type="identifier"><mjx-c>𝑐</mjx-c></mjx-mi></mjx-math></mjx-container> electrons hybridizing with a lattice of localized <mjx-container ctxtmenu_counter="274" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="0"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-role="latinletter" data-semantic-speech="f" data-semantic-type="identifier"><mjx-c>𝑓</mjx-c></mjx-mi></mjx-math></mjx-container> electrons. At zero temperature, it exhibits a much-studied quantum phase transition from a Kondo phase to a Ruderman-Kittel-Kasuya-Yosida (RKKY) phase when the hybridization is decreased through a so-called Kondo breakdown quantum critical point (KB QCP). There, Kondo screening of <mjx-container ctxtmenu_counter="275" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="0"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-role="latinletter" data-semantic-speech="f" data-semantic-type="identifier"><mjx-c>𝑓</mjx-c></mjx-mi></mjx-math></mjx-container> spins by <mjx-container ctxtmenu_counter="276" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="0"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-role="latinletter" data-semantic-speech="c" data-semantic-type="identifier"><mjx-c>𝑐</mjx-c></mjx-mi></mjx-math></mjx-container> electrons breaks down, so that <mjx-container ctxtmenu_counter="277" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="0"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-role="latinletter" data-semantic-speech="f" data-semantic-type="identifier"><mjx-c>𝑓</mjx-c></mjx-mi></mjx-math></mjx-container> excitations change their character from somewhat itinerant to mainly localized, while <mjx-container ctxtmenu_counter="278" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree
{"title":"Emergent Properties of the Periodic Anderson Model: A High-Resolution, Real-Frequency Study of Heavy-Fermion Quantum Criticality","authors":"Andreas Gleis, Seung-Sup B. Lee, Gabriel Kotliar, Jan von Delft","doi":"10.1103/physrevx.14.041036","DOIUrl":"https://doi.org/10.1103/physrevx.14.041036","url":null,"abstract":"We study paramagnetic quantum criticality in the periodic Anderson model (PAM) using cellular dynamical mean-field theory (CDMFT), with the numerical renormalization group (NRG) as a cluster impurity solver. The PAM describes itinerant <mjx-container ctxtmenu_counter=\"273\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"0\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"c\" data-semantic-type=\"identifier\"><mjx-c>𝑐</mjx-c></mjx-mi></mjx-math></mjx-container> electrons hybridizing with a lattice of localized <mjx-container ctxtmenu_counter=\"274\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"0\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"f\" data-semantic-type=\"identifier\"><mjx-c>𝑓</mjx-c></mjx-mi></mjx-math></mjx-container> electrons. At zero temperature, it exhibits a much-studied quantum phase transition from a Kondo phase to a Ruderman-Kittel-Kasuya-Yosida (RKKY) phase when the hybridization is decreased through a so-called Kondo breakdown quantum critical point (KB QCP). There, Kondo screening of <mjx-container ctxtmenu_counter=\"275\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"0\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"f\" data-semantic-type=\"identifier\"><mjx-c>𝑓</mjx-c></mjx-mi></mjx-math></mjx-container> spins by <mjx-container ctxtmenu_counter=\"276\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"0\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"c\" data-semantic-type=\"identifier\"><mjx-c>𝑐</mjx-c></mjx-mi></mjx-math></mjx-container> electrons breaks down, so that <mjx-container ctxtmenu_counter=\"277\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"0\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"f\" data-semantic-type=\"identifier\"><mjx-c>𝑓</mjx-c></mjx-mi></mjx-math></mjx-container> excitations change their character from somewhat itinerant to mainly localized, while <mjx-container ctxtmenu_counter=\"278\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"105 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Pub Date : 2024-11-07DOI: 10.1103/physrevx.14.041037
Simon Munyan, Sina Ahadi, Binghao Guo, Arman Rashidi, Susanne Stemmer
The quantum Wigner crystal is a many-body state where Coulombic repulsion quenches the kinetic energy of electrons, causing them to crystallize into a lattice. Experimental realization of a quantum Wigner crystal at zero magnetic field has been a long-sought goal. Here, we report on the experimental evidence of a Wigner solid in ultra-thin films of cadmium arsenide (<mjx-container ctxtmenu_counter="12" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(7 (2 0 1) 6 (5 3 4))"><mjx-mrow data-semantic-annotation="clearspeak:unit" data-semantic-children="2,5" data-semantic-content="6" data-semantic- data-semantic-owns="2 6 5" data-semantic-role="implicit" data-semantic-speech="upper C d 3 upper A s 2" data-semantic-type="infixop"><mjx-msub data-semantic-children="0,1" data-semantic- data-semantic-owns="0 1" data-semantic-parent="7" data-semantic-role="unknown" data-semantic-type="subscript"><mjx-mrow><mjx-mi data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="identifier"><mjx-c noic="true" style="padding-top: 0.706em;">C</mjx-c><mjx-c style="padding-top: 0.706em;">d</mjx-c></mjx-mi></mjx-mrow><mjx-script style="vertical-align: -0.15em;"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="integer" data-semantic-type="number" size="s"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub><mjx-mo data-semantic-added="true" data-semantic- data-semantic-operator="infixop," data-semantic-parent="7" data-semantic-role="multiplication" data-semantic-type="operator"><mjx-c></mjx-c></mjx-mo><mjx-msub data-semantic-children="3,4" data-semantic- data-semantic-owns="3 4" data-semantic-parent="7" data-semantic-role="unknown" data-semantic-type="subscript"><mjx-mrow><mjx-mi data-semantic-font="normal" data-semantic- data-semantic-parent="5" data-semantic-role="unknown" data-semantic-type="identifier"><mjx-c noic="true" style="padding-top: 0.662em;">A</mjx-c><mjx-c style="padding-top: 0.662em;">s</mjx-c></mjx-mi></mjx-mrow><mjx-script style="vertical-align: -0.15em;"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="5" data-semantic-role="integer" data-semantic-type="number" size="s"><mjx-c>2</mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-mrow></mjx-math></mjx-container>) at zero magnetic field. We show that a finite bias depins the domains and produces an unusually sharp-threshold current-voltage behavior. Hysteresis and voltage fluctuations point to domain motion across the pinning potential and disappear at finite temperature as thermal fluctuations overcome the potential. The application of a small magnetic field destroys the Wigner solid, pointing to an unconventional origin. We use Landau-level spectroscopy to show that the formation of the
{"title":"Evidence of Zero-Field Wigner Solids in Ultrathin Films of Cadmium Arsenide","authors":"Simon Munyan, Sina Ahadi, Binghao Guo, Arman Rashidi, Susanne Stemmer","doi":"10.1103/physrevx.14.041037","DOIUrl":"https://doi.org/10.1103/physrevx.14.041037","url":null,"abstract":"The quantum Wigner crystal is a many-body state where Coulombic repulsion quenches the kinetic energy of electrons, causing them to crystallize into a lattice. Experimental realization of a quantum Wigner crystal at zero magnetic field has been a long-sought goal. Here, we report on the experimental evidence of a Wigner solid in ultra-thin films of cadmium arsenide (<mjx-container ctxtmenu_counter=\"12\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(7 (2 0 1) 6 (5 3 4))\"><mjx-mrow data-semantic-annotation=\"clearspeak:unit\" data-semantic-children=\"2,5\" data-semantic-content=\"6\" data-semantic- data-semantic-owns=\"2 6 5\" data-semantic-role=\"implicit\" data-semantic-speech=\"upper C d 3 upper A s 2\" data-semantic-type=\"infixop\"><mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-owns=\"0 1\" data-semantic-parent=\"7\" data-semantic-role=\"unknown\" data-semantic-type=\"subscript\"><mjx-mrow><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\"><mjx-c noic=\"true\" style=\"padding-top: 0.706em;\">C</mjx-c><mjx-c style=\"padding-top: 0.706em;\">d</mjx-c></mjx-mi></mjx-mrow><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub><mjx-mo data-semantic-added=\"true\" data-semantic- data-semantic-operator=\"infixop,\" data-semantic-parent=\"7\" data-semantic-role=\"multiplication\" data-semantic-type=\"operator\"><mjx-c></mjx-c></mjx-mo><mjx-msub data-semantic-children=\"3,4\" data-semantic- data-semantic-owns=\"3 4\" data-semantic-parent=\"7\" data-semantic-role=\"unknown\" data-semantic-type=\"subscript\"><mjx-mrow><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"5\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\"><mjx-c noic=\"true\" style=\"padding-top: 0.662em;\">A</mjx-c><mjx-c style=\"padding-top: 0.662em;\">s</mjx-c></mjx-mi></mjx-mrow><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"5\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c>2</mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-mrow></mjx-math></mjx-container>) at zero magnetic field. We show that a finite bias depins the domains and produces an unusually sharp-threshold current-voltage behavior. Hysteresis and voltage fluctuations point to domain motion across the pinning potential and disappear at finite temperature as thermal fluctuations overcome the potential. The application of a small magnetic field destroys the Wigner solid, pointing to an unconventional origin. We use Landau-level spectroscopy to show that the formation of the","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"95 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142598152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Pub Date : 2024-11-06DOI: 10.1103/physrevx.14.041035
Fabian H. L. Essler, Werner Krauth
Virtually all Markov-chain Monte Carlo algorithms used for sampling a given distribution are reversible, and they satisfy the detailed-balance condition. For local chains, this leads to a slow, diffusive exploration of sample space. Significant speedups can be achieved through nonreversible algorithms with the given distribution as a targeted steady state. However, nonreversible algorithms for sampling are difficult to set up and to analyze, and exact speedup results for interacting many-particle systems are very rare. Here, we introduce the “lifted” totally asymmetric simple exclusion process (TASEP) as an exactly solvable paradigm for nonreversible many-particle Markov chains. It samples the same hard-sphere distribution as the Metropolis algorithm for symmetrically diffusing hard-core particles on a one-dimensional lattice. We solve the lifted TASEP by an unusual kind of coordinate Bethe ansatz and show that it exhibits polynomial (in particle number) speedups in the relaxation time for the asymptotic approach of the steady state, as well as the nonasymptotic mixing time, compared to both Metropolis and Kardar-Parisi-Zhang-based dynamics. The lifted TASEP is the reduction onto the one-dimensional lattice of the successful hard-sphere event-chain Monte Carlo algorithm, and we discuss that it can likewise be generalized to soft interaction potentials.
{"title":"Lifted TASEP: A Solvable Paradigm for Speeding up Many-Particle Markov Chains","authors":"Fabian H. L. Essler, Werner Krauth","doi":"10.1103/physrevx.14.041035","DOIUrl":"https://doi.org/10.1103/physrevx.14.041035","url":null,"abstract":"Virtually all Markov-chain Monte Carlo algorithms used for sampling a given distribution are reversible, and they satisfy the detailed-balance condition. For local chains, this leads to a slow, diffusive exploration of sample space. Significant speedups can be achieved through nonreversible algorithms with the given distribution as a targeted steady state. However, nonreversible algorithms for sampling are difficult to set up and to analyze, and exact speedup results for interacting many-particle systems are very rare. Here, we introduce the “lifted” totally asymmetric simple exclusion process (TASEP) as an exactly solvable paradigm for nonreversible many-particle Markov chains. It samples the same hard-sphere distribution as the Metropolis algorithm for symmetrically diffusing hard-core particles on a one-dimensional lattice. We solve the lifted TASEP by an unusual kind of coordinate Bethe ansatz and show that it exhibits polynomial (in particle number) speedups in the relaxation time for the asymptotic approach of the steady state, as well as the nonasymptotic mixing time, compared to both Metropolis and Kardar-Parisi-Zhang-based dynamics. The lifted TASEP is the reduction onto the one-dimensional lattice of the successful hard-sphere event-chain Monte Carlo algorithm, and we discuss that it can likewise be generalized to soft interaction potentials.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"69 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Pub Date : 2024-11-06DOI: 10.1103/physrevx.14.041034
Thibaut Arnoulx de Pirey, Yariv Kafri, Sriram Ramaswamy
We show that an inclusion placed inside a dilute Stokesian suspension of microswimmers induces power-law number-density modulations and flows. These take a different form depending on whether the inclusion is held fixed by an external force—for example, an optical tweezer—or if it is free. When the inclusion is held in place, the far-field fluid flow is a Stokeslet, while the microswimmer density decays as <mjx-container ctxtmenu_counter="31" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-children="0,7" data-semantic-content="1" data-semantic- data-semantic-owns="0 1 7" data-semantic-role="division" data-semantic-speech="1 divided by r Superscript 2 plus epsilon" data-semantic-structure="(8 0 1 (7 2 (6 3 4 5)))" data-semantic-type="infixop"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="8" data-semantic-role="integer" data-semantic-type="number"><mjx-c>1</mjx-c></mjx-mn><mjx-mo data-semantic- data-semantic-operator="infixop,/" data-semantic-parent="8" data-semantic-role="division" data-semantic-type="operator"><mjx-c>/</mjx-c></mjx-mo><mjx-msup data-semantic-children="2,6" data-semantic- data-semantic-owns="2 6" data-semantic-parent="8" data-semantic-role="latinletter" data-semantic-type="superscript"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="7" data-semantic-role="latinletter" data-semantic-type="identifier"><mjx-c>𝑟</mjx-c></mjx-mi><mjx-script style="vertical-align: 0.363em;"><mjx-mrow data-semantic-children="3,5" data-semantic-content="4" data-semantic- data-semantic-owns="3 4 5" data-semantic-parent="7" data-semantic-role="addition" data-semantic-type="infixop" size="s"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="6" data-semantic-role="integer" data-semantic-type="number"><mjx-c>2</mjx-c></mjx-mn><mjx-mo data-semantic- data-semantic-operator="infixop,+" data-semantic-parent="6" data-semantic-role="addition" data-semantic-type="operator"><mjx-c>+</mjx-c></mjx-mo><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="6" data-semantic-role="greekletter" data-semantic-type="identifier"><mjx-c>𝜀</mjx-c></mjx-mi></mjx-mrow></mjx-script></mjx-msup></mjx-math></mjx-container>, with <mjx-container ctxtmenu_counter="32" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="0"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-role="latinletter" data-semantic-speech="r" data-semantic-type="identifier"><mjx-c>𝑟</mjx-c></mjx-mi></mjx-math></mjx-container> the distance from the inclusion and <mjx-container ctxtmenu
{"title":"Anomalous Long-Ranged Influence of an Inclusion in Momentum-Conserving Active Fluids","authors":"Thibaut Arnoulx de Pirey, Yariv Kafri, Sriram Ramaswamy","doi":"10.1103/physrevx.14.041034","DOIUrl":"https://doi.org/10.1103/physrevx.14.041034","url":null,"abstract":"We show that an inclusion placed inside a dilute Stokesian suspension of microswimmers induces power-law number-density modulations and flows. These take a different form depending on whether the inclusion is held fixed by an external force—for example, an optical tweezer—or if it is free. When the inclusion is held in place, the far-field fluid flow is a Stokeslet, while the microswimmer density decays as <mjx-container ctxtmenu_counter=\"31\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-children=\"0,7\" data-semantic-content=\"1\" data-semantic- data-semantic-owns=\"0 1 7\" data-semantic-role=\"division\" data-semantic-speech=\"1 divided by r Superscript 2 plus epsilon\" data-semantic-structure=\"(8 0 1 (7 2 (6 3 4 5)))\" data-semantic-type=\"infixop\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"8\" data-semantic-role=\"integer\" data-semantic-type=\"number\"><mjx-c>1</mjx-c></mjx-mn><mjx-mo data-semantic- data-semantic-operator=\"infixop,/\" data-semantic-parent=\"8\" data-semantic-role=\"division\" data-semantic-type=\"operator\"><mjx-c>/</mjx-c></mjx-mo><mjx-msup data-semantic-children=\"2,6\" data-semantic- data-semantic-owns=\"2 6\" data-semantic-parent=\"8\" data-semantic-role=\"latinletter\" data-semantic-type=\"superscript\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"7\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c>𝑟</mjx-c></mjx-mi><mjx-script style=\"vertical-align: 0.363em;\"><mjx-mrow data-semantic-children=\"3,5\" data-semantic-content=\"4\" data-semantic- data-semantic-owns=\"3 4 5\" data-semantic-parent=\"7\" data-semantic-role=\"addition\" data-semantic-type=\"infixop\" size=\"s\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"6\" data-semantic-role=\"integer\" data-semantic-type=\"number\"><mjx-c>2</mjx-c></mjx-mn><mjx-mo data-semantic- data-semantic-operator=\"infixop,+\" data-semantic-parent=\"6\" data-semantic-role=\"addition\" data-semantic-type=\"operator\"><mjx-c>+</mjx-c></mjx-mo><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"6\" data-semantic-role=\"greekletter\" data-semantic-type=\"identifier\"><mjx-c>𝜀</mjx-c></mjx-mi></mjx-mrow></mjx-script></mjx-msup></mjx-math></mjx-container>, with <mjx-container ctxtmenu_counter=\"32\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"0\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"r\" data-semantic-type=\"identifier\"><mjx-c>𝑟</mjx-c></mjx-mi></mjx-math></mjx-container> the distance from the inclusion and <mjx-container ctxtmenu","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"86 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Pub Date : 2024-11-05DOI: 10.1103/physrevx.14.041032
Emanuel Hubenschmid, Thiago L. M. Guedes, Guido Burkard
Following recent progress in the experimental application of electro-optic sampling to the detection of the quantum fluctuations of the electromagnetic-field ground state and ultrabroadband squeezed states on a subcycle scale, we propose an approach to elevate broadband electro-optic sampling from a spectroscopic method to a full quantum tomography scheme, able to reconstruct a free-space quantum state directly in the time domain. By combining two recently developed methods to theoretically describe quantum electro-optic sampling, we analytically relate the photon-count probability distribution of the electro-optic signal to a transformed phase-space quasiprobability distribution of the sampled quantum state as a function of the time delay between the sampled midinfrared pulsed state and an ultrabroadband near-infrared probe pulse. We catalog and analyze sources of noise and show that in quantum electro-optic sampling with an ultrabroadband probe pulse one can expect to observe thermalization due to entanglement breaking. Mitigation of the thermalization noise enables a tomographic reconstruction of broadband quantum states while granting access to its dynamics on a subcycle scale.
{"title":"Optical Time-Domain Quantum State Tomography on a Subcycle Scale","authors":"Emanuel Hubenschmid, Thiago L. M. Guedes, Guido Burkard","doi":"10.1103/physrevx.14.041032","DOIUrl":"https://doi.org/10.1103/physrevx.14.041032","url":null,"abstract":"Following recent progress in the experimental application of electro-optic sampling to the detection of the quantum fluctuations of the electromagnetic-field ground state and ultrabroadband squeezed states on a subcycle scale, we propose an approach to elevate broadband electro-optic sampling from a spectroscopic method to a full quantum tomography scheme, able to reconstruct a free-space quantum state directly in the time domain. By combining two recently developed methods to theoretically describe quantum electro-optic sampling, we analytically relate the photon-count probability distribution of the electro-optic signal to a transformed phase-space quasiprobability distribution of the sampled quantum state as a function of the time delay between the sampled midinfrared pulsed state and an ultrabroadband near-infrared probe pulse. We catalog and analyze sources of noise and show that in quantum electro-optic sampling with an ultrabroadband probe pulse one can expect to observe thermalization due to entanglement breaking. Mitigation of the thermalization noise enables a tomographic reconstruction of broadband quantum states while granting access to its dynamics on a subcycle scale.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"47 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Pub Date : 2024-11-04DOI: 10.1103/physrevx.14.041030
Xuntao Wu, Haoxiong Yan, Gustav Andersson, Alexander Anferov, Ming-Han Chou, Christopher R. Conner, Joel Grebel, Yash J. Joshi, Shiheng Li, Jacob M. Miller, Rhys G. Povey, Hong Qiao, Andrew N. Cleland
Superconducting qubits provide a promising approach to large-scale fault-tolerant quantum computing. However, qubit connectivity on a planar surface is typically restricted to only a few neighboring qubits. Achieving longer-range and more flexible connectivity, which is particularly appealing in light of recent developments in error-correcting codes, however, usually involves complex multilayer packaging and external cabling, which is resource intensive and can impose fidelity limitations. Here, we propose and realize a high-speed on-chip quantum processor that supports reconfigurable all-to-all coupling with a large on-off ratio. We implement the design in a four-node quantum processor, built with a modular design comprising a wiring substrate coupled to two separate qubit-bearing substrates, each including two single-qubit nodes. We use this device to demonstrate reconfigurable controlled-<mjx-container ctxtmenu_counter="131" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="0"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-role="latinletter" data-semantic-speech="upper Z" data-semantic-type="identifier"><mjx-c>𝑍</mjx-c></mjx-mi></mjx-math></mjx-container> gates across all qubit pairs, with a benchmarked average fidelity of <mjx-container ctxtmenu_counter="132" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-children="0,1,5,4" data-semantic-content="1,4" data-semantic- data-semantic-owns="0 1 5 4" data-semantic-role="sequence" data-semantic-speech="96.00 percent sign plus or minus 0.08 percent sign" data-semantic-structure="(6 0 1 (5 2 3) 4)" data-semantic-type="punctuated"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="6" data-semantic-role="float" data-semantic-type="number"><mjx-c noic="true" style="padding-top: 0.646em;">9</mjx-c><mjx-c noic="true" style="padding-top: 0.646em;">6</mjx-c><mjx-c noic="true" style="padding-top: 0.646em;">.</mjx-c><mjx-c noic="true" style="padding-top: 0.646em;">0</mjx-c><mjx-c style="padding-top: 0.646em;">0</mjx-c></mjx-mn><mjx-mo data-semantic- data-semantic-operator="punctuated" data-semantic-parent="6" data-semantic-role="unknown" data-semantic-type="punctuation"><mjx-c>%</mjx-c></mjx-mo><mjx-mrow data-semantic-added="true" data-semantic-children="3" data-semantic-content="2" data-semantic- data-semantic-owns="2 3" data-semantic-parent="6" data-semantic-role="addition" data-semantic-type="prefixop" space="3"><mjx-mo data-semantic- data-semantic-operator="prefixop,±" data-semantic-parent="5" data-semantic-role="addition" data-semantic-type="operator"><mjx-c>±</mjx-c></mjx-mo><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic-
{"title":"Modular Quantum Processor with an All-to-All Reconfigurable Router","authors":"Xuntao Wu, Haoxiong Yan, Gustav Andersson, Alexander Anferov, Ming-Han Chou, Christopher R. Conner, Joel Grebel, Yash J. Joshi, Shiheng Li, Jacob M. Miller, Rhys G. Povey, Hong Qiao, Andrew N. Cleland","doi":"10.1103/physrevx.14.041030","DOIUrl":"https://doi.org/10.1103/physrevx.14.041030","url":null,"abstract":"Superconducting qubits provide a promising approach to large-scale fault-tolerant quantum computing. However, qubit connectivity on a planar surface is typically restricted to only a few neighboring qubits. Achieving longer-range and more flexible connectivity, which is particularly appealing in light of recent developments in error-correcting codes, however, usually involves complex multilayer packaging and external cabling, which is resource intensive and can impose fidelity limitations. Here, we propose and realize a high-speed on-chip quantum processor that supports reconfigurable all-to-all coupling with a large on-off ratio. We implement the design in a four-node quantum processor, built with a modular design comprising a wiring substrate coupled to two separate qubit-bearing substrates, each including two single-qubit nodes. We use this device to demonstrate reconfigurable controlled-<mjx-container ctxtmenu_counter=\"131\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"0\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"upper Z\" data-semantic-type=\"identifier\"><mjx-c>𝑍</mjx-c></mjx-mi></mjx-math></mjx-container> gates across all qubit pairs, with a benchmarked average fidelity of <mjx-container ctxtmenu_counter=\"132\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-children=\"0,1,5,4\" data-semantic-content=\"1,4\" data-semantic- data-semantic-owns=\"0 1 5 4\" data-semantic-role=\"sequence\" data-semantic-speech=\"96.00 percent sign plus or minus 0.08 percent sign\" data-semantic-structure=\"(6 0 1 (5 2 3) 4)\" data-semantic-type=\"punctuated\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"6\" data-semantic-role=\"float\" data-semantic-type=\"number\"><mjx-c noic=\"true\" style=\"padding-top: 0.646em;\">9</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.646em;\">6</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.646em;\">.</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.646em;\">0</mjx-c><mjx-c style=\"padding-top: 0.646em;\">0</mjx-c></mjx-mn><mjx-mo data-semantic- data-semantic-operator=\"punctuated\" data-semantic-parent=\"6\" data-semantic-role=\"unknown\" data-semantic-type=\"punctuation\"><mjx-c>%</mjx-c></mjx-mo><mjx-mrow data-semantic-added=\"true\" data-semantic-children=\"3\" data-semantic-content=\"2\" data-semantic- data-semantic-owns=\"2 3\" data-semantic-parent=\"6\" data-semantic-role=\"addition\" data-semantic-type=\"prefixop\" space=\"3\"><mjx-mo data-semantic- data-semantic-operator=\"prefixop,±\" data-semantic-parent=\"5\" data-semantic-role=\"addition\" data-semantic-type=\"operator\"><mjx-c>±</mjx-c></mjx-mo><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- ","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"67 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Pub Date : 2024-11-04DOI: 10.1103/physrevx.14.041031
Tibor Rakovszky, Sarang Gopalakrishnan, Curt von Keyserlingk
The steady states of dynamical processes can exhibit stable nontrivial phases, which can also serve as fault-tolerant classical or quantum memories. For Markovian quantum (classical) dynamics, these steady states are extremal eigenvectors of the non-Hermitian operators that generate the dynamics, i.e., quantum channels (Markov chains). However, since these operators are non-Hermitian, their spectra are an unreliable guide to dynamical relaxation timescales or to stability against perturbations. We propose an alternative dynamical criterion for a steady state to be in a stable phase, which we name uniformity: Informally, our criterion amounts to requiring that, under sufficiently small local perturbations of the dynamics, the unperturbed and perturbed steady states are related to one another by a finite-time dissipative evolution. We show that this criterion implies many of the properties one would want from any reasonable definition of a phase. We prove that uniformity is satisfied in a canonical classical cellular automaton, and we provide numerical evidence that the gap determines the relaxation rate between nearby steady states in the same phase, a situation we conjecture holds generically whenever uniformity is satisfied. We further conjecture some sufficient conditions for a channel to exhibit uniformity and therefore stability.
{"title":"Defining Stable Phases of Open Quantum Systems","authors":"Tibor Rakovszky, Sarang Gopalakrishnan, Curt von Keyserlingk","doi":"10.1103/physrevx.14.041031","DOIUrl":"https://doi.org/10.1103/physrevx.14.041031","url":null,"abstract":"The steady states of dynamical processes can exhibit stable nontrivial phases, which can also serve as fault-tolerant classical or quantum memories. For Markovian quantum (classical) dynamics, these steady states are extremal eigenvectors of the non-Hermitian operators that generate the dynamics, i.e., quantum channels (Markov chains). However, since these operators are non-Hermitian, their spectra are an unreliable guide to dynamical relaxation timescales or to stability against perturbations. We propose an alternative dynamical criterion for a steady state to be in a stable phase, which we name uniformity: Informally, our criterion amounts to requiring that, under sufficiently small local perturbations of the dynamics, the unperturbed and perturbed steady states are related to one another by a finite-time dissipative evolution. We show that this criterion implies many of the properties one would want from any reasonable definition of a phase. We prove that uniformity is satisfied in a canonical classical cellular automaton, and we provide numerical evidence that the gap determines the relaxation rate between nearby steady states in the same phase, a situation we conjecture holds generically whenever uniformity is satisfied. We further conjecture some sufficient conditions for a channel to exhibit uniformity and therefore stability.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"90 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
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