Pub Date : 2020-03-10DOI: 10.1146/annurev-conmatphys-031119-050738
M. Warner
Liquid crystal elastomers and glasses suffer huge length changes on heating, illumination, exposure to humidity, etc. A challenge is to program these changes to give a complex mechanical response for micromachines and soft robotics. Also desirable can be strong response, where bend is avoided in favor of stretch and compression, even in the slender shells that are our subject. A new mechanics paradigm arises from such materials—spatially programmed anisotropy allows a spatially varying metric to develop upon stimulation, with evolving Gaussian curvature, topography changes, and superstrong actuation. We call this metric mechanics or topographical mechanics. Thus programmed, liquid crystalline solids meet the above aims. A frontier is the complete programming and control of topography, driving both Gaussian and mean curvature evolution. That, and smart shells, which sense and self-regulate, and exotic new realizations of anisotropic responsive structures, are our concluding themes.
{"title":"Topographic Mechanics and Applications of Liquid Crystalline Solids","authors":"M. Warner","doi":"10.1146/annurev-conmatphys-031119-050738","DOIUrl":"https://doi.org/10.1146/annurev-conmatphys-031119-050738","url":null,"abstract":"Liquid crystal elastomers and glasses suffer huge length changes on heating, illumination, exposure to humidity, etc. A challenge is to program these changes to give a complex mechanical response for micromachines and soft robotics. Also desirable can be strong response, where bend is avoided in favor of stretch and compression, even in the slender shells that are our subject. A new mechanics paradigm arises from such materials—spatially programmed anisotropy allows a spatially varying metric to develop upon stimulation, with evolving Gaussian curvature, topography changes, and superstrong actuation. We call this metric mechanics or topographical mechanics. Thus programmed, liquid crystalline solids meet the above aims. A frontier is the complete programming and control of topography, driving both Gaussian and mean curvature evolution. That, and smart shells, which sense and self-regulate, and exotic new realizations of anisotropic responsive structures, are our concluding themes.","PeriodicalId":7925,"journal":{"name":"Annual Review of Condensed Matter Physics","volume":" ","pages":""},"PeriodicalIF":22.6,"publicationDate":"2020-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-conmatphys-031119-050738","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49345376","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 : 2020-03-10DOI: 10.1146/annurev-conmatphys-031119-050704
A. Leggett
I present some rather selective reminiscences of my long career in physics, from my doctoral work to the present. I do not spend time on topics such as the nuclear magnetic resonance behavior of 3He, as I have reviewed the history extensively elsewhere, but rather concentrate, first, on my long-running project to make condensed matter physics relevant to questions in the foundations of quantum mechanics, and second, on various rather “quirky” problems such as an attempt to amplify the effects of the parity violation due to the weak interaction to a macroscopic level, and an unconventional proposal for the mechanism of the first-order phase transition between the A and B phases of superfluid liquid 3He.
{"title":"Matchmaking Between Condensed Matter and Quantum Foundations, and Other Stories: My Six Decades in Physics","authors":"A. Leggett","doi":"10.1146/annurev-conmatphys-031119-050704","DOIUrl":"https://doi.org/10.1146/annurev-conmatphys-031119-050704","url":null,"abstract":"I present some rather selective reminiscences of my long career in physics, from my doctoral work to the present. I do not spend time on topics such as the nuclear magnetic resonance behavior of 3He, as I have reviewed the history extensively elsewhere, but rather concentrate, first, on my long-running project to make condensed matter physics relevant to questions in the foundations of quantum mechanics, and second, on various rather “quirky” problems such as an attempt to amplify the effects of the parity violation due to the weak interaction to a macroscopic level, and an unconventional proposal for the mechanism of the first-order phase transition between the A and B phases of superfluid liquid 3He.","PeriodicalId":7925,"journal":{"name":"Annual Review of Condensed Matter Physics","volume":" ","pages":""},"PeriodicalIF":22.6,"publicationDate":"2020-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-conmatphys-031119-050704","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46835377","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 : 2020-03-10DOI: 10.1146/annurev-conmatphys-031119-050752
H. Chaté
Active matter physics is about systems in which energy is dissipated at some local level to produce work. This is a generic situation, particularly in the living world but not only. What is at stake is the understanding of the fascinating, sometimes counterintuitive, emerging phenomena observed, from collective motion in animal groups to in vitro dynamical self-organization of motor proteins and biofilaments. Dry aligning dilute active matter (DADAM) is a corner of the multidimensional, fast-growing domain of active matter that has both historical and theoretical importance for the entire field. This restrictive setting only involves self-propulsion/activity, alignment, and noise, yet unexpected collective properties can emerge from it. This review provides a personal but synthetic and coherent overview of DADAM, focusing on the collective-level phenomenology of simple active particle models representing basic classes of systems and on the solutions of the continuous hydrodynamic theories that can be derived from them. The obvious fact that orientational order is advected by the aligning active particles at play is shown to be at the root of the most striking properties of DADAM systems: ( a) direct transitions to orientational order are not observed; ( b) instead generic phase separation occurs with a coexistence phase involving inhomogeneous nonlinear structures; ( c) orientational order, which can be long range even in two dimensions, is accompanied by long-range correlations and anomalous fluctuations; ( d) defects are not point-like, topologically bound objects.
{"title":"Dry Aligning Dilute Active Matter","authors":"H. Chaté","doi":"10.1146/annurev-conmatphys-031119-050752","DOIUrl":"https://doi.org/10.1146/annurev-conmatphys-031119-050752","url":null,"abstract":"Active matter physics is about systems in which energy is dissipated at some local level to produce work. This is a generic situation, particularly in the living world but not only. What is at stake is the understanding of the fascinating, sometimes counterintuitive, emerging phenomena observed, from collective motion in animal groups to in vitro dynamical self-organization of motor proteins and biofilaments. Dry aligning dilute active matter (DADAM) is a corner of the multidimensional, fast-growing domain of active matter that has both historical and theoretical importance for the entire field. This restrictive setting only involves self-propulsion/activity, alignment, and noise, yet unexpected collective properties can emerge from it. This review provides a personal but synthetic and coherent overview of DADAM, focusing on the collective-level phenomenology of simple active particle models representing basic classes of systems and on the solutions of the continuous hydrodynamic theories that can be derived from them. The obvious fact that orientational order is advected by the aligning active particles at play is shown to be at the root of the most striking properties of DADAM systems: ( a) direct transitions to orientational order are not observed; ( b) instead generic phase separation occurs with a coexistence phase involving inhomogeneous nonlinear structures; ( c) orientational order, which can be long range even in two dimensions, is accompanied by long-range correlations and anomalous fluctuations; ( d) defects are not point-like, topologically bound objects.","PeriodicalId":7925,"journal":{"name":"Annual Review of Condensed Matter Physics","volume":" ","pages":""},"PeriodicalIF":22.6,"publicationDate":"2020-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-conmatphys-031119-050752","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42110506","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 : 2020-03-01Epub Date: 2019-12-06DOI: 10.1146/annurev-conmatphys-031218-013231
Shiladitya Banerjee, Margaret L Gardel, Ulrich S Schwarz
Actin is the main protein used by biological cells to adapt their structure and mechanics to their needs. Cellular adaptation is made possible by molecular processes that strongly depend on mechanics. The actin cytoskeleton is also an active material that continuously consumes energy. This allows for dynamical processes that are possible only out of equilibrium and opens up the possibility for multiple layers of control that have evolved around this single protein.Here we discuss the actin cytoskeleton from the viewpoint of physics as an active adaptive material that can build structures superior to man-made soft matter systems. Not only can actin be used to build different network architectures on demand and in an adaptive manner, but it also exhibits the dynamical properties of feedback systems, like excitability, bistability, or oscillations. Therefore, it is a prime example of how biology couples physical structure and information flow and a role model for biology-inspired metamaterials.
{"title":"The Actin Cytoskeleton as an Active Adaptive Material.","authors":"Shiladitya Banerjee, Margaret L Gardel, Ulrich S Schwarz","doi":"10.1146/annurev-conmatphys-031218-013231","DOIUrl":"10.1146/annurev-conmatphys-031218-013231","url":null,"abstract":"<p><p>Actin is the main protein used by biological cells to adapt their structure and mechanics to their needs. Cellular adaptation is made possible by molecular processes that strongly depend on mechanics. The actin cytoskeleton is also an active material that continuously consumes energy. This allows for dynamical processes that are possible only out of equilibrium and opens up the possibility for multiple layers of control that have evolved around this single protein.Here we discuss the actin cytoskeleton from the viewpoint of physics as an active adaptive material that can build structures superior to man-made soft matter systems. Not only can actin be used to build different network architectures on demand and in an adaptive manner, but it also exhibits the dynamical properties of feedback systems, like excitability, bistability, or oscillations. Therefore, it is a prime example of how biology couples physical structure and information flow and a role model for biology-inspired metamaterials.</p>","PeriodicalId":7925,"journal":{"name":"Annual Review of Condensed Matter Physics","volume":"11 1","pages":"421-439"},"PeriodicalIF":14.3,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7748259/pdf/nihms-1648253.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38733491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-30DOI: 10.1146/ANNUREV-CONMATPHYS-031119-050725
Ezequiel Ferrero, L. Foini, T. Giamarchi, A. Kolton, A. Rosso
The thermally activated creep motion of an elastic interface weakly driven on a disordered landscape is one of the best examples of glassy universal dynamics. Its understanding has evolved over the past 30 years thanks to a fruitful interplay among elegant scaling arguments, sophisticated analytical calculations, efficient optimization algorithms, and creative experiments. In this article, starting from the pioneer arguments, we review the main theoretical and experimental results that lead to the current physical picture of the creep regime. In particular, we discuss recent works unveiling the collective nature of such ultraslow motion in terms of elementary activated events. We show that these events control the mean velocity of the interface and cluster into “creep avalanches” statistically similar to the deterministic avalanches observed at the depinning critical threshold. The associated spatiotemporal patterns of activated events have been recently observed in experiments with magnetic domain walls. The emergent physical picture is expected to be relevant for a large family of disordered systems presenting thermally activated dynamics.
{"title":"Creep Motion of Elastic Interfaces Driven in a Disordered Landscape","authors":"Ezequiel Ferrero, L. Foini, T. Giamarchi, A. Kolton, A. Rosso","doi":"10.1146/ANNUREV-CONMATPHYS-031119-050725","DOIUrl":"https://doi.org/10.1146/ANNUREV-CONMATPHYS-031119-050725","url":null,"abstract":"The thermally activated creep motion of an elastic interface weakly driven on a disordered landscape is one of the best examples of glassy universal dynamics. Its understanding has evolved over the past 30 years thanks to a fruitful interplay among elegant scaling arguments, sophisticated analytical calculations, efficient optimization algorithms, and creative experiments. In this article, starting from the pioneer arguments, we review the main theoretical and experimental results that lead to the current physical picture of the creep regime. In particular, we discuss recent works unveiling the collective nature of such ultraslow motion in terms of elementary activated events. We show that these events control the mean velocity of the interface and cluster into “creep avalanches” statistically similar to the deterministic avalanches observed at the depinning critical threshold. The associated spatiotemporal patterns of activated events have been recently observed in experiments with magnetic domain walls. The emergent physical picture is expected to be relevant for a large family of disordered systems presenting thermally activated dynamics.","PeriodicalId":7925,"journal":{"name":"Annual Review of Condensed Matter Physics","volume":" ","pages":""},"PeriodicalIF":22.6,"publicationDate":"2020-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42084924","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 : 2019-06-30DOI: 10.1146/annurev-conmatphys-031119-050611
M. Bar, R. Großmann, S. Heidenreich, F. Peruani
A wide range of experimental systems including gliding, swarming and swimming bacteria, in vitro motility assays, and shaken granular media are commonly described as self-propelled rods. Large ensembles of those entities display a large variety of self-organized, collective phenomena, including the formation of moving polar clusters, polar and nematic dynamic bands, mobility-induced phase separation, topological defects, and mesoscale turbulence, among others. Here, we give a brief survey of experimental observations and review the theoretical description of self-propelled rods. Our focus is on the emergent pattern formation of ensembles of dry self-propelled rods governed by short-ranged, contact mediated interactions and their wet counterparts that are also subject to long-ranged hydrodynamic flows. Altogether, self-propelled rods provide an overarching theme covering many aspects of active matter containing well-explored limiting cases. Their collective behavior not only bridges the well-studied regimes of polar self-propelled particles and active nematics, and includes active phase separation, but also reveals a rich variety of new patterns.
{"title":"Self-Propelled Rods: Insights and Perspectives for Active Matter","authors":"M. Bar, R. Großmann, S. Heidenreich, F. Peruani","doi":"10.1146/annurev-conmatphys-031119-050611","DOIUrl":"https://doi.org/10.1146/annurev-conmatphys-031119-050611","url":null,"abstract":"A wide range of experimental systems including gliding, swarming and swimming bacteria, in vitro motility assays, and shaken granular media are commonly described as self-propelled rods. Large ensembles of those entities display a large variety of self-organized, collective phenomena, including the formation of moving polar clusters, polar and nematic dynamic bands, mobility-induced phase separation, topological defects, and mesoscale turbulence, among others. Here, we give a brief survey of experimental observations and review the theoretical description of self-propelled rods. Our focus is on the emergent pattern formation of ensembles of dry self-propelled rods governed by short-ranged, contact mediated interactions and their wet counterparts that are also subject to long-ranged hydrodynamic flows. Altogether, self-propelled rods provide an overarching theme covering many aspects of active matter containing well-explored limiting cases. Their collective behavior not only bridges the well-studied regimes of polar self-propelled particles and active nematics, and includes active phase separation, but also reveals a rich variety of new patterns.","PeriodicalId":7925,"journal":{"name":"Annual Review of Condensed Matter Physics","volume":" ","pages":""},"PeriodicalIF":22.6,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-conmatphys-031119-050611","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45746658","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 : 2019-06-25DOI: 10.1146/annurev-conmatphys-031218-013125
C. P'epin, D. Chakraborty, M. Grandadam, S. Sarkar
The physics of the pseudogap phase of high-temperature cuprate superconductors has been an enduring mystery over the past 30 years. The ubiquitous presence of the pseudogap phase in underdoped cuprates suggests that understanding it is key to unraveling the origin of high-temperature superconductivity. We review various theoretical approaches to this problem, emphasizing the concept of emergent symmetries in the underdoped region of those compounds. We differentiate these theories by considering a few fundamental questions related to the rich phenomenology of these materials. Lastly, we discuss a recent idea regarding two kinds of entangled preformed pairs that open a gap at the pseudogap onset temperature, T*, through a specific Higgs mechanism. We review the experimental consequences of this line of thought.
{"title":"Fluctuations and the Higgs Mechanism in Underdoped Cuprates","authors":"C. P'epin, D. Chakraborty, M. Grandadam, S. Sarkar","doi":"10.1146/annurev-conmatphys-031218-013125","DOIUrl":"https://doi.org/10.1146/annurev-conmatphys-031218-013125","url":null,"abstract":"The physics of the pseudogap phase of high-temperature cuprate superconductors has been an enduring mystery over the past 30 years. The ubiquitous presence of the pseudogap phase in underdoped cuprates suggests that understanding it is key to unraveling the origin of high-temperature superconductivity. We review various theoretical approaches to this problem, emphasizing the concept of emergent symmetries in the underdoped region of those compounds. We differentiate these theories by considering a few fundamental questions related to the rich phenomenology of these materials. Lastly, we discuss a recent idea regarding two kinds of entangled preformed pairs that open a gap at the pseudogap onset temperature, T*, through a specific Higgs mechanism. We review the experimental consequences of this line of thought.","PeriodicalId":7925,"journal":{"name":"Annual Review of Condensed Matter Physics","volume":"1 1","pages":""},"PeriodicalIF":22.6,"publicationDate":"2019-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-conmatphys-031218-013125","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63958313","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 : 2019-06-22DOI: 10.1146/annurev-conmatphys-031119-050813
R. Shimano, N. Tsuji
When the continuous symmetry of a physical system is spontaneously broken, two types of collective modes typically emerge: the amplitude and the phase modes of the order-parameter fluctuation. For superconductors, the amplitude mode is referred to most recently as the Higgs mode as it is a condensed-matter analog of a Higgs boson in particle physics. Higgs mode is a scalar excitation of the order parameter, distinct from charge or spin fluctuations, and thus does not couple to electromagnetic fields linearly. This is why the Higgs mode in superconductors has evaded experimental observations for over a half century after the initial theoretical prediction, except for a charge-density-wave coexisting system. With the advance of nonlinear and time-resolved terahertz spectroscopy techniques, however, it has become possible to study the Higgs mode through the nonlinear light–Higgs coupling. In this review, we overview recent progress in the study of the Higgs mode in superconductors.
{"title":"Higgs Mode in Superconductors","authors":"R. Shimano, N. Tsuji","doi":"10.1146/annurev-conmatphys-031119-050813","DOIUrl":"https://doi.org/10.1146/annurev-conmatphys-031119-050813","url":null,"abstract":"When the continuous symmetry of a physical system is spontaneously broken, two types of collective modes typically emerge: the amplitude and the phase modes of the order-parameter fluctuation. For superconductors, the amplitude mode is referred to most recently as the Higgs mode as it is a condensed-matter analog of a Higgs boson in particle physics. Higgs mode is a scalar excitation of the order parameter, distinct from charge or spin fluctuations, and thus does not couple to electromagnetic fields linearly. This is why the Higgs mode in superconductors has evaded experimental observations for over a half century after the initial theoretical prediction, except for a charge-density-wave coexisting system. With the advance of nonlinear and time-resolved terahertz spectroscopy techniques, however, it has become possible to study the Higgs mode through the nonlinear light–Higgs coupling. In this review, we overview recent progress in the study of the Higgs mode in superconductors.","PeriodicalId":7925,"journal":{"name":"Annual Review of Condensed Matter Physics","volume":" ","pages":""},"PeriodicalIF":22.6,"publicationDate":"2019-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-conmatphys-031119-050813","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48853153","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 : 2019-05-31DOI: 10.1146/annurev-conmatphys-031119-050605
M. Kjaergaard, M. Schwartz, Jochen Braumuller, P. Krantz, J. Wang, S. Gustavsson, W. Oliver
Superconducting qubits are leading candidates in the race to build a quantum computer capable of realizing computations beyond the reach of modern supercomputers. The superconducting qubit modality has been used to demonstrate prototype algorithms in the noisy intermediate-scale quantum (NISQ) technology era, in which non-error-corrected qubits are used to implement quantum simulations and quantum algorithms. With the recent demonstrations of multiple high-fidelity, two-qubit gates as well as operations on logical qubits in extensible superconducting qubit systems, this modality also holds promise for the longer-term goal of building larger-scale error-corrected quantum computers. In this brief review, we discuss several of the recent experimental advances in qubit hardware, gate implementations, readout capabilities, early NISQ algorithm implementations, and quantum error correction using superconducting qubits. Although continued work on many aspects of this technology is certainly necessary, the pace of both conceptual and technical progress in recent years has been impressive, and here we hope to convey the excitement stemming from this progress.
{"title":"Superconducting Qubits: Current State of Play","authors":"M. Kjaergaard, M. Schwartz, Jochen Braumuller, P. Krantz, J. Wang, S. Gustavsson, W. Oliver","doi":"10.1146/annurev-conmatphys-031119-050605","DOIUrl":"https://doi.org/10.1146/annurev-conmatphys-031119-050605","url":null,"abstract":"Superconducting qubits are leading candidates in the race to build a quantum computer capable of realizing computations beyond the reach of modern supercomputers. The superconducting qubit modality has been used to demonstrate prototype algorithms in the noisy intermediate-scale quantum (NISQ) technology era, in which non-error-corrected qubits are used to implement quantum simulations and quantum algorithms. With the recent demonstrations of multiple high-fidelity, two-qubit gates as well as operations on logical qubits in extensible superconducting qubit systems, this modality also holds promise for the longer-term goal of building larger-scale error-corrected quantum computers. In this brief review, we discuss several of the recent experimental advances in qubit hardware, gate implementations, readout capabilities, early NISQ algorithm implementations, and quantum error correction using superconducting qubits. Although continued work on many aspects of this technology is certainly necessary, the pace of both conceptual and technical progress in recent years has been impressive, and here we hope to convey the excitement stemming from this progress.","PeriodicalId":7925,"journal":{"name":"Annual Review of Condensed Matter Physics","volume":" ","pages":""},"PeriodicalIF":22.6,"publicationDate":"2019-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-conmatphys-031119-050605","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46217211","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 : 2019-05-30DOI: 10.1146/annurev-conmatphys-031119-050658
D. Else, C. Monroe, C. Nayak, N. Yao
Experimental advances have allowed for the exploration of nearly isolated quantum many-body systems whose coupling to an external bath is very weak. A particularly interesting class of such systems is those that do not thermalize under their own isolated quantum dynamics. In this review, we highlight the possibility for such systems to exhibit new nonequilibrium phases of matter. In particular, we focus on discrete time crystals, which are many-body phases of matter characterized by a spontaneously broken discrete time-translation symmetry. We give a definition of discrete time crystals from several points of view, emphasizing that they are a nonequilibrium phenomenon that is stabilized by many-body interactions, with no analog in noninteracting systems. We explain the theory behind several proposed models of discrete time crystals, and compare several recent realizations, in different experimental contexts.
{"title":"Discrete Time Crystals","authors":"D. Else, C. Monroe, C. Nayak, N. Yao","doi":"10.1146/annurev-conmatphys-031119-050658","DOIUrl":"https://doi.org/10.1146/annurev-conmatphys-031119-050658","url":null,"abstract":"Experimental advances have allowed for the exploration of nearly isolated quantum many-body systems whose coupling to an external bath is very weak. A particularly interesting class of such systems is those that do not thermalize under their own isolated quantum dynamics. In this review, we highlight the possibility for such systems to exhibit new nonequilibrium phases of matter. In particular, we focus on discrete time crystals, which are many-body phases of matter characterized by a spontaneously broken discrete time-translation symmetry. We give a definition of discrete time crystals from several points of view, emphasizing that they are a nonequilibrium phenomenon that is stabilized by many-body interactions, with no analog in noninteracting systems. We explain the theory behind several proposed models of discrete time crystals, and compare several recent realizations, in different experimental contexts.","PeriodicalId":7925,"journal":{"name":"Annual Review of Condensed Matter Physics","volume":" ","pages":""},"PeriodicalIF":22.6,"publicationDate":"2019-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1146/annurev-conmatphys-031119-050658","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41959366","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}