Physical Review Research最新文献

{"title":"Experimental certification of level dynamics in single-photon emitters","authors":"Lukáš Lachman, Ilya P. Radko, Maxime Bergamin, Ulrik L. Andersen, Alexander Huck, Radim Filip","doi":"10.1103/physrevresearch.6.033254","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033254","url":null,"abstract":"Emitters of single photons are essential resources for emerging quantum technologies and developed within different platforms including nonlinear optics and atomic and solid-state systems. The energy-level structures of emission processes are critical for reaching and controlling high-quality sources. The most commonly applied test uses a Hanbury Brown and Twiss (HBT) setup to determine the emitter energy-level structure based on fitting temporal correlations of photon detection events. However, only partial information about the emission process is extracted from such detection, that might be followed by an inconclusive fitting of the data. This process predetermines our limited ability to quantify and understand the dynamics in the photon emission process that are of importance for the applications in communication, sensing, and computing. In this work, we present a complete analysis based on all normalized coincidences between detection and no-detection events recorded in the same HBT setup to certify expected properties of an emitted photonic state. As a proof of concept we apply our methodology to single nitrogen-vacancy centers in diamond, in which case the certification conclusively rejects a model based on a two-level emitter that radiates a photonic state mixed with any classical noise background.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ballistic deposition with memory: A new universality class of surface growth with a new scaling law","authors":"Ahmed Roman, Ruomin Zhu, Ilya Nemenman","doi":"10.1103/physrevresearch.6.l032053","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.l032053","url":null,"abstract":"Motivated by recent experimental studies in microbiology, we suggest modifying the classic ballistic deposition model of surface growth, where the memory of a deposition at a site induces more depositions at that site or its neighbors. By studying the statistics of surfaces in this model, we obtain three independent critical exponents: the growth exponent <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>β</mi><mo>=</mo><mn>5</mn><mo>/</mo><mn>4</mn></mrow></math>, the roughening exponent <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>α</mi><mo>=</mo><mn>2</mn></mrow></math>, and the new (size) exponent <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>γ</mi><mo>=</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math>. The model requires modifying the Family-Vicsek scaling, resulting in the dynamical exponent <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>z</mi><mo>=</mo><mfrac><mrow><mi>α</mi><mo>+</mo><mi>γ</mi></mrow><mi>β</mi></mfrac><mo>=</mo><mn>2</mn></mrow></math>. This modified scaling collapses the surface width vs time curves for various lattice sizes. This previously unobserved universality class of surface growth could describe the surface properties of a wide range of natural systems.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"No drama in two-dimensional black hole evaporation","authors":"Jonathan Barenboim, Andrei V. Frolov, Gabor Kunstatter","doi":"10.1103/physrevresearch.6.l032055","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.l032055","url":null,"abstract":"We numerically calculate the spacetime describing the formation and evaporation of a regular black hole in 2D dilaton gravity. The apparent horizons evaporate smoothly in finite time to form a compact trapped region. We nevertheless see rich dynamics: an antitrapped region forms alongside the black hole and additional compact trapped and antitrapped regions are formed by backreaction effects as the mass radiates away. The spacetime is asymptotically flat at future null infinity and is free of singularities and Cauchy horizons. These results suggest that the evaporation of regular 2D black holes is unitary.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anticipating critical transitions in multidimensional systems driven by time- and state-dependent noise","authors":"Andreas Morr, Keno Riechers, Leonardo Rydin Gorjão, Niklas Boers","doi":"10.1103/physrevresearch.6.033251","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033251","url":null,"abstract":"Anticipating bifurcation-induced transitions in dynamical systems has gained relevance in various fields of the natural, social, and economic sciences. Before the annihilation of a system's equilibrium point by means of a bifurcation, the system's internal feedbacks that stabilize the initial state weaken and eventually vanish, a process referred to as critical slowing down (CSD). In one-dimensional systems, this motivates the use of variance and lag-1 autocorrelation as indicators of CSD. However, the applicability of variance is limited to time- and state-independent driving noise, strongly constraining the generality of this CSD indicator. In multidimensional systems, the use of these indicators is often preceded by a dimension reduction in order to obtain a one-dimensional time series. Many common techniques for such an extraction of a one-dimensional time series generally incur the risk of missing CSD in practice. Here, we propose a data-driven approach based on estimating a multidimensional Langevin equation to detect local stability changes and anticipate bifurcation-induced transitions in systems with generally time- and state-dependent noise. Our approach substantially generalizes the conditions under which CSD can reliably be detected, as demonstrated in a suite of examples. In contrast to existing approaches, changes in deterministic dynamics can be clearly discriminated from changes in the driving noise using our method. This substantially reduces the risk of false or missed alarms of conventional CSD indicators in settings with time-dependent or multiplicative noise. In multidimensional systems, our method can greatly advance the understanding of the coupling between system components and can avoid risks of missing CSD due to dimension reduction, which existing approaches suffer from.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing quantum state tomography via resource-efficient attention-based neural networks","authors":"Adriano Macarone Palmieri, Guillem Müller-Rigat, Anubhav Kumar Srivastava, Maciej Lewenstein, Grzegorz Rajchel-Mieldzioć, Marcin Płodzień","doi":"10.1103/physrevresearch.6.033248","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033248","url":null,"abstract":"In this paper, we propose a method for denoising experimental density matrices that combines standard quantum state tomography with an attention-based neural network architecture. The algorithm learns the noise from the data itself, without <i>a priori</i> knowledge of its sources. Firstly, we show how the proposed protocol can improve the averaged fidelity of reconstruction over linear inversion and maximum likelihood estimation in the finite-statistics regime, reducing at least by an order of magnitude the amount of necessary training data. Next, we demonstrate its use for out-of-distribution data in realistic scenarios. In particular, we consider squeezed states of few spins in the presence of depolarizing noise and measurement/calibration errors and certify its metrologically useful entanglement content. The protocol introduced here targets experiments involving few degrees of freedom and afflicted by a significant amount of unspecified noise. These include NISQ devices and platforms such as trapped ions or photonic qudits.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining the quantum signatures of optimal excitation energy transfer","authors":"Jonah S. Peter, Raphael Holzinger, Stefan Ostermann, Susanne F. Yelin","doi":"10.1103/physrevresearch.6.033252","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033252","url":null,"abstract":"The transport and capture of photo-induced electronic excitations is of fundamental interest to the design of energy efficient quantum technologies and to the study of potential quantum effects in biology. Using a simple quantum optical model, we examine the influence of coherence, entanglement, and cooperative dissipation on the transport and capture of excitation energy. We demonstrate that the rate of energy extraction is optimized under conditions that minimize the quantum coherence and entanglement of the system, which is a consequence of spontaneous parity time-reversal symmetry breaking. We then examine the effects of vibrational disorder and show that dephasing can be used to enhance the transport of delocalized excitations in settings relevant to biological photosynthesis. Our results highlight the rich, emergent behavior associated with the quantum-to-classical transition with relevance to the design of room-temperature quantum devices.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase modulation of directed transport, energy diffusion, and quantum scrambling in a Floquet non-Hermitian system","authors":"Wen-Lei Zhao, Guanling Li, Jie Liu","doi":"10.1103/physrevresearch.6.033249","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033249","url":null,"abstract":"We investigate both analytically and numerically the wavepacket's dynamics in momentum space for a Floquet non-Hermitian system with a periodically kicked driven potential. We have deduced the exact expression of a time-evolving wavepacket under the condition of quantum resonance. With this analytical expression, we can investigate thoroughly the temporal behaviors of the directed transport, mean energy, and quantum scrambling. We find interestingly that, by tuning the relative phase between the real part and imaginary part of the kicking potential, one can manipulate the directed transport, mean energy, and quantum scrambling efficiently: When the phase equals to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>π</mi><mo>/</mo><mn>2</mn></mrow></math>, we observe a maximum directed transport and mean energy, while a minimum scrambling phenomenon protected by the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"script\">PT</mi></math> symmetry; when the phase is <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>π</mi></math>, both the directed transport and the time dependence of the energy are suppressed; in contrast, the quantum scrambling is enhanced by the non-Hermiticity. For the quantum nonresonance case, we numerically find that the quantum interference effects lead to dynamical localization, characterized by the suppression of the directed transport, the time dependence of the energy, and quantum scrambling. Interestingly, these suppression effects can be adjusted by the phase of the non-Hermitian kicking potential. Possible applications of our findings are discussed.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tunable multiphoton bundles emission in a Kerr-type two-photon Jaynes-Cummings model","authors":"Jing Tang, Yuangang Deng","doi":"10.1103/physrevresearch.6.033247","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033247","url":null,"abstract":"We present a study on manipulation and enhancement of multiphoton bundles emission under a moderate atom-cavity coupling, by constructing a two-photon Jaynes-Cummings model integrated with Kerr nonlinearity in a single atom-cavity system. We show that the vacuum-Rabi splittings for the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>n</mi><mi>th</mi></math> dressed states can be significantly enhanced by Kerr interaction. This remarkable enhancement in energy-spectrum anharmonicity with the well-resolved multiphoton resonance facilitates the generation of special nonclassical states beyond the strong-coupling limit in the experiment. In particular, both two- and three-photon blockades are observed with adjusting the amplitude of the cavity-driving or atom-pump fields. Moreover, we discover that transitions between two- and three-photon bundles can be achieved through tuning the atom-cavity detuning or Kerr nonlinearity. It further showcases the three-photon blockade is substantially strengthened when both the cavity and atomic fields are jointly driven. Our proposal unveils a pathway for realizing highly controllable nonclassical states and quantum devices with combining two-photon Jaynes-Cummings interactions and Kerr nonlinearity, which may pave the way for versatile applications in quantum information science, e.g., all-optical switches and transistors.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical properties and electronic structure of the two-gap superconductor V2Ga5","authors":"P.-Y. Cheng, Mohamed Oudah, T.-L. Hung, C.-E. Hsu, C.-C. Chang, J.-Y. Haung, T.-C. Liu, C.-M. Cheng, M.-N. Ou, W.-T. Chen, L. Z. Deng, C.-C. Lee, Y.-Y. Chen, C.-N. Kuo, C.-S. Lue, Janna Machts, Kenji M. Kojima, Alannah M. Hallas, C.-L. Huang","doi":"10.1103/physrevresearch.6.033253","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033253","url":null,"abstract":"We present a thorough investigation of the physical properties and superconductivity of the binary intermetallic <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">V</mi><mn>2</mn></msub><msub><mi>Ga</mi><mn>5</mn></msub></mrow></math>. Electrical resistivity and specific heat measurements show that <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">V</mi><mn>2</mn></msub><msub><mi>Ga</mi><mn>5</mn></msub></mrow></math> enters its superconducting state below <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>T</mi><mrow><mi>s</mi><mi>c</mi></mrow></msub><mo>=</mo></mrow></math> 3.5 K, with a critical field of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>H</mi><mrow><mrow><mi mathvariant=\"normal\">c</mi><mn>2</mn></mrow><mo>,</mo><mo>⊥</mo><mi mathvariant=\"normal\">c</mi></mrow></msub><mrow><mo>(</mo><msub><mi>H</mi><mrow><mrow><mi mathvariant=\"normal\">c</mi><mn>2</mn></mrow><mo>,</mo><mo>|</mo><mo>|</mo><mi mathvariant=\"normal\">c</mi></mrow></msub><mo>)</mo></mrow><mo>=</mo><mn>6.5</mn><mrow><mo>(</mo><mn>4.1</mn><mo>)</mo></mrow></mrow></math> kOe. With <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>H</mi><mo>⊥</mo><mi>c</mi></mrow></math>, the peak effect was observed in resistivity measurements, indicating the ultrahigh quality of the single crystal studied. The resistivity measurements under high pressure reveal that the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>T</mi><mrow><mi>s</mi><mi>c</mi></mrow></msub></math> is suppressed linearly with pressure and reaches absolute zero around 20 GPa. Specific heat and muon spin relaxation measurements indicate that the two-gap <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>s</mi></math>-wave model best describes the superconductivity of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">V</mi><mn>2</mn></msub><msub><mi>Ga</mi><mn>5</mn></msub></mrow></math>. The bands near the Fermi level around the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Z</mi></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"normal\">Γ</mi></math> points are observed and analyzed by the angle-resolved photoemission spectroscopy measurements and first-principles band structure calculations. We therefore conclude that <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">V</mi><mn>2</mn></msub><msub><mi>Ga</mi><mn>5</mn></msub></mrow></math> is a phonon-mediated two-gap <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>s</mi></math>-wave superconductor.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnonic Otto thermal machine","authors":"Nicolas Vidal-Silva, Francisco J. Peña, Roberto E. Troncoso, Patricio Vargas","doi":"10.1103/physrevresearch.6.033164","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033164","url":null,"abstract":"We propose a quasistatic magnon-based Otto thermal machine in two-dimensional (2D) magnetic insulators. The thermodynamical cycles are engineered by exposing a magnon spin system to thermal baths at different temperatures and tuning the Dzyaloshinskii-Moriya (DM) interaction. We find that a thermal gas of magnons converts a fraction of heat into energy in the form of work, where the efficiency is maximized for specific values of DM, reaching the corresponding Carnot efficiency. We witness a positive to negative net work transition during the cycle that marks the onset of a refrigeratorlike behavior. The work produced by the magnonic Otto engine enhances the magnon chemical potential. The last enables a spin accumulation that might result in the pumping of spin currents at the interfaces of metal-magnet heterostructures. Our work opens possibilities for the efficient leverage of conventional two-dimensional magnets.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141946065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}