Physical review research最新文献

{"title":"Micromotion-based DC sensing using continuously tracked trajectories of dipolar coupled nuclear spins","authors":"Ozgur Sahin, Hawraa Al Asadi, Paul M. Schindler, Arjun Pillai, Erica Sanchez, Matthew Markham, Mark Elo, Maxwell McAllister, Emanuel Druga, Christoph Fleckenstein, Marin Bukov, Ashok Ajoy","doi":"10.1103/bgdc-rgkd","DOIUrl":"https://doi.org/10.1103/bgdc-rgkd","url":null,"abstract":"We report an experimental approach to excite, stabilize, and continuously track Bloch sphere trajectories of dipolar-coupled nuclear spins in a solid. We demonstrate these capabilities on a model system of hyperpolarized <a:math xmlns:a=\"http://www.w3.org/1998/Math/MathML\"> <a:mmultiscripts> <a:mi mathvariant=\"normal\">C</a:mi> <a:mprescripts/> <a:none/> <a:mn>13</a:mn> </a:mmultiscripts> </a:math> nuclear spins in diamond. We elucidate a method to drive, and preserve, the motion of spins in complex three-dimensional trajectories for over <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\"> <c:mrow> <c:msubsup> <c:mi>T</c:mi> <c:mn>2</c:mn> <c:mo>′</c:mo> </c:msubsup> <c:mo>&gt;</c:mo> <c:mn>27</c:mn> <c:mspace width=\"0.16em\"/> <c:mi mathvariant=\"normal\">s</c:mi> </c:mrow> </c:math> even in the presence of interspin coupling. Indeed, without quantum control, interspin interactions lead to rapid spin decay in <f:math xmlns:f=\"http://www.w3.org/1998/Math/MathML\"> <f:mrow> <f:msubsup> <f:mi>T</f:mi> <f:mn>2</f:mn> <f:mo>*</f:mo> </f:msubsup> <f:mo>≈</f:mo> <f:mn>1.5</f:mn> <f:mspace width=\"0.16em\"/> <f:mi>ms</f:mi> </f:mrow> </f:math> . Furthermore, we show that the motion of the spins can be continuously tracked in three dimensions on the Bloch sphere for over <h:math xmlns:h=\"http://www.w3.org/1998/Math/MathML\"> <h:mrow> <h:mn>35</h:mn> <h:mspace width=\"0.16em\"/> <h:mi mathvariant=\"normal\">s</h:mi> </h:mrow> </h:math> . During this time the spins complete <k:math xmlns:k=\"http://www.w3.org/1998/Math/MathML\"> <k:mrow> <k:mo>&gt;</k:mo> <k:mn>68</k:mn> <k:mspace width=\"0.16em\"/> <k:mn>000</k:mn> </k:mrow> </k:math> closed precession orbits, exhibiting high stability and robustness against error. Leveraging these long-lived, robust spin trajectories we devise a novel nonequilibrium quantum sensing scheme for DC magnetic fields, based on micromotion dynamics, and without a static counterpart. Sensing here proceeds for the entire <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\"> <m:msubsup> <m:mi>T</m:mi> <m:mn>2</m:mn> <m:mo>′</m:mo> </m:msubsup> </m:math> period, orders of magnitude longer than <n:math xmlns:n=\"http://www.w3.org/1998/Math/MathML\"> <n:msubsup> <n:mi>T</n:mi> <n:mn>2</n:mn> <n:mo>*</n:mo> </n:msubsup> </n:math> , and operates in the dense sensor limit, yielding significant sensitivity improvements. Our results suggest new ways to stabilize and interrogate strongly coupled quantum systems through periodic driving and portend powerful applications of rigid spin orbits in quantum sensing.","PeriodicalId":520315,"journal":{"name":"Physical review research","volume":"7 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147912304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exactly solvable statistical physics models for large neuronal populations.","authors":"Christopher W Lynn, Qiwei Yu, Rich Pang, William Bialek, Stephanie E Palmer","doi":"10.1103/PhysRevResearch.7.L022039","DOIUrl":"10.1103/PhysRevResearch.7.L022039","url":null,"abstract":"<p><p>Maximum-entropy methods provide a principled path connecting measurements of neural activity directly to statistical physics models, and this approach has been successful for populations of <math><mi>N</mi> <mo>~</mo> <mn>100</mn></math> neurons. As <math><mi>N</mi></math> increases in new experiments, we enter an undersampled regime where we have to choose which observables should be constrained in the maximum-entropy construction. The best choice is the one that provides the greatest reduction in entropy, defining a \"minimax entropy\" principle. This principle becomes tractable if we restrict attention to correlations among pairs of neurons that link together into a tree; we can find the best tree efficiently, and the underlying statistical physics models are exactly solved. We use this approach to analyze experiments on <math><mi>N</mi> <mo>~</mo> <mn>1500</mn></math> neurons in the mouse hippocampus, and we find that the resulting model captures key features of collective activity in the network.</p>","PeriodicalId":520315,"journal":{"name":"Physical review research","volume":"7 2","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13451037/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148698709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time heterogeneity of the Förster radius from dipole orientational dynamics impacts single-molecule Förster resonance energy transfer experiments.","authors":"David Frost, Keisha Cook, Hugo Sanabria","doi":"10.1103/physrevresearch.7.023014","DOIUrl":"10.1103/physrevresearch.7.023014","url":null,"abstract":"<p><p>Förster resonance energy transfer (FRET) is a quantum mechanical process governing the nonradiative energy transfer between coupled electric dipoles. Its strong distance dependence makes it a widely used as a \"molecular ruler\" in biology, chemistry, and physics. In single-molecule FRET (smFRET) experiments employing time-resolved confocal microscopy, deviations from the theoretical Förster relationship between FRET efficiency and donor fluorescence lifetime-termed dynamic shifts-provide insight into underlying molecular conformational dynamics. A key challenge in interpreting these shifts is disentangling contributions from the intrinsic motion of the fluorescent dyes from those of the biomolecular system under study. We present a novel theoretical framework based on Langevin dynamics to model the stochastic translational and rotational motion of dye linkers, incorporating first-principles physics and chemical constraints consistent with molecular dynamics simulations. Our results demonstrate that the dominant factor influencing dynamic shifts in smFRET is the relative orientational fluctuations of the dyes' electric dipole moments, rather than their accessible spatial volumes. These findings refine the theoretical foundations of FRET and provide the most precise estimates of FRET efficiency to date, enhancing its utility as a molecular-scale probe of dynamic processes.</p>","PeriodicalId":520315,"journal":{"name":"Physical review research","volume":"7 2","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13098721/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147794665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lyapunov theory demonstrating a fundamental limit on the speed of systems consolidation.","authors":"Alireza Alemi, Emre R F Aksay, Mark S Goldman","doi":"10.1103/physrevresearch.7.023174","DOIUrl":"10.1103/physrevresearch.7.023174","url":null,"abstract":"<p><p>The nervous system reorganizes memories from an early site to a late site, a commonly observed feature of learning and memory systems known as systems consolidation. Previous work has suggested learning rules by which consolidation may occur. Here, we provide conditions under which such rules are guaranteed to lead to stable convergence of learning and consolidation. We use the theory of Lyapunov functions, which enforces stability by requiring learning rules to decrease an energy-like (Lyapunov) function. We present the theory in the context of a simple circuit architecture motivated by classic models of cerebellum-mediated learning and consolidation. Stability is only guaranteed if the learning rate in the late stage is not faster than the learning rate in the early stage. Further, the slower the learning rate at the late stage, the larger the perturbation the system can tolerate with a guarantee of stability. We provide intuition for this result by mapping a simple example consolidation model to a damped driven oscillator system and showing that the ratio of early- to late-stage learning rates in the consolidation model can be directly identified with the oscillator's damping ratio. We then apply the theory to modeling the tuning by the cerebellum of a well-characterized analog short-term memory system, the oculomotor neural integrator, and find similar stability conditions. This work suggests the power of the Lyapunov approach to provide constraints on nervous system function.</p>","PeriodicalId":520315,"journal":{"name":"Physical review research","volume":"7 2","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12392100/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144985697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Symmetry, gauge freedoms, and the interpretability of sequence-function relationships.","authors":"Anna Posfai, David M McCandlish, Justin B Kinney","doi":"10.1103/physrevresearch.7.023005","DOIUrl":"https://doi.org/10.1103/physrevresearch.7.023005","url":null,"abstract":"<p><p>Quantitative models that describe how biological sequences encode functional activities are ubiquitous in modern biology. One important aspect of these models is that they commonly exhibit gauge freedoms, i.e., directions in parameter space that do not affect model predictions. In physics, gauge freedoms arise when physical theories are formulated in ways that respect fundamental symmetries. However, the connections that gauge freedoms in models of sequence-function relationships have to the symmetries of sequence space have yet to be systematically studied. Here we study the gauge freedoms of models that respect a specific symmetry of sequence space: the group of position-specific character permutations. We find that gauge freedoms arise when model parameters transform under redundant irreducible matrix representations of this group. Based on this finding, we describe an \"embedding distillation\" procedure that enables analytic calculation of the number of independent gauge freedoms, as well as efficient computation of a sparse basis for the space of gauge freedoms. We also study how parameter transformation behavior affects parameter interpretability. We find that in many (and possibly all) nontrivial models, the ability to interpret individual model parameters as quantifying intrinsic allelic effects requires that gauge freedoms be present. This finding establishes an incompatibility between two distinct notions of parameter interpretability. Our work thus advances the understanding of symmetries, gauge freedoms, and parameter interpretability in sequence-function relationships.</p>","PeriodicalId":520315,"journal":{"name":"Physical review research","volume":"7 2","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12363380/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144985627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Waveguide QED with dissipative light-matter couplings","authors":"Xing‐Liang Dong, Fuli Li, Zongping Gong, Franco Nori","doi":"10.1103/physrevresearch.7.l012036","DOIUrl":"https://doi.org/10.1103/physrevresearch.7.l012036","url":null,"abstract":"Dissipative light-matter coupling plays a vital role in non-Hermitian physics, but it remains largely unexplored in waveguide QED systems. In this work, we find that by employing pseudo-Hermitian symmetry rather than anti-<a:math xmlns:a=\"http://www.w3.org/1998/Math/MathML\"><a:mi mathvariant=\"script\">PT</a:mi></a:math> symmetry, the concept of dissipative coupling could be generalized and applied to the field of waveguide QED. This leads to a series of intriguing results, such as spontaneous breaking of pseudo-Hermitian symmetry across the exceptional points (EPs), level attraction between the bound states, and critical transition across the EPs for the population of quantum emitters in the bound state. Thanks to the tunability of photonic bands in crystal waveguides, we also demonstrate that dissipative light-matter coupling leads to the emergence of nonstandard third-order exceptional points with chiral spatial profiles in a topological waveguide QED system. This work provides a promising paradigm for studying non-Hermitian quantum phenomena in waveguide QED systems.","PeriodicalId":520315,"journal":{"name":"Physical review research","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"http://link.aps.org/pdf/10.1103/PhysRevResearch.7.L012036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147381964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conditional fluctuation theorems and entropy production for monitored quantum systems under imperfect detection","authors":"Mar Ferri-Cortés, José A. Almanza-Marrero, Rosa López, Roberta Zambrini, Gonzalo Manzano","doi":"10.1103/physrevresearch.7.013077","DOIUrl":"https://doi.org/10.1103/physrevresearch.7.013077","url":null,"abstract":"The thermodynamic behavior of Markovian open quantum systems can be described at the level of fluctuations by using continuous monitoring approaches. However, practical applications require assessing imperfect detection schemes, where the definition of main thermodynamic quantities becomes subtle and universal fluctuation relations are unknown. Here, we fill this gap by deriving a universal fluctuation relation that links thermodynamic entropy production and information-theoretical irreversibility along single trajectories in inefficient monitoring setups. This relation provides as a corollary an irreversibility estimator of dissipation using imperfect detection records that lower bounds the underlying entropy production at the level of visible trajectories. We illustrate our findings with a driven-dissipative two-level system following quantum jump trajectories and discuss the experimental applicability of our results for thermodynamic inference.","PeriodicalId":520315,"journal":{"name":"Physical review research","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147889744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decoherence-free many-body Hamiltonians in nonlinear waveguide quantum electrodynamics","authors":"Aviv Karnieli, Offek Tziperman, Charles Roques‐Carmes, Shanhui Fan","doi":"10.1103/physrevresearch.7.l012014","DOIUrl":"https://doi.org/10.1103/physrevresearch.7.l012014","url":null,"abstract":"Enhancing interactions in many-body quantum systems, while protecting them from environmental decoherence, is at the heart of many quantum technologies. Waveguide quantum electrodynamics is a promising platform for achieving this, as it hosts infinite-range interactions and decoherence-free subspaces of quantum emitters. However, as coherent interactions between emitters are typically washed out in the wavelength-spacing regime hosting decoherence-free states, coherent control over the latter becomes limited, and many-body Hamiltonians in this important regime remain out of reach. Here we show that by incorporating emitter arrays with nonlinear waveguides hosting parametric gain, we obtain a unique class of many-body interaction Hamiltonians with coupling strengths that increase with emitter spacing, and persist even for wavelength-spaced arrays. We then propose to use these Hamiltonians to coherently generate decoherence-free states directly from the ground state, using only global squeezing drives, without the need for local addressing of individual emitters. Interestingly, we find that the dynamics approaches a unitary evolution in the limit of weak intrawaveguide squeezing, and we discuss potential experimental realizations of this effect. Our results pave the way towards coherent control protocols in waveguide quantum electrodynamics, with applications including quantum computing, simulation, memory, and nonclassical light generation.","PeriodicalId":520315,"journal":{"name":"Physical review research","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147917322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Counting statistics of ultrabroadband microwave photons","authors":"Simon Beaudoin, Edouard Pinsolle, Bertrand Reulet","doi":"10.1103/physrevresearch.6.043238","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.043238","url":null,"abstract":"We report measurements of counting statistics, average and variance, of microwave photons of ill-defined frequency: bichromatic photons, i.e., photons involving two well separated frequencies, and “white” broadband photons. Our setup allows for the analysis of single photonic modes of arbitrary waveform over the 1–10 GHz frequency range. The photon statistics are obtained by on-the-fly numerical calculation from the sampled time-dependent voltage. Using an <a:math xmlns:a=\"http://www.w3.org/1998/Math/MathML\"><a:mrow><a:mi>ac</a:mi><a:mo>+</a:mo><a:mi>dc</a:mi></a:mrow></a:math> biased tunnel junction as a source of quantum microwave, we report an ultrawide squeezing spectrum representing a competitive source for entanglement generation (up to 0.9 billion measured entangled bits per second) easily achievable experimentally. We also report the observation of quantum steering by the tunnel junction, and show how the presence of squeezing of a broadband mode implies the existence of entanglement between two modes it encompasses. Published by the American Physical Society 2024","PeriodicalId":520315,"journal":{"name":"Physical review research","volume":"6 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"http://link.aps.org/pdf/10.1103/PhysRevResearch.6.043238","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147891690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of microwave phase noise on diamond quantum sensing.","authors":"Andris Berzins, Maziar Saleh Ziabari, Yaser Silani, Ilja Fescenko, Joshua T Damron, John F Barry, Andrey Jarmola, Pauli Kehayias, Bryan A Richards, Janis Smits, Victor M Acosta","doi":"10.1103/physrevresearch.6.043148","DOIUrl":"10.1103/physrevresearch.6.043148","url":null,"abstract":"<p><p>Precision optical measurements of the electron-spin precession of nitrogen-vacancy (NV) centers in diamond form the basis of numerous applications. The most sensitivity-demanding applications, such as femtotesla magnetometry, require the ability to measure changes in GHz spin transition frequencies at the sub-millihertz level, corresponding to a fractional resolution of better than 10^-12. Here we study the impact of microwave (MW) phase noise on the response of an NV sensor. Fluctuations of the phase of the MW waveform cause undesired rotations of the NV spin state. These fluctuations are imprinted in the optical readout signal and, left unmitigated, are indistinguishable from magnetic-field noise. We show that the phase noise of several common commercial MW generators results in an effective <math><mtext>pT</mtext> <mspace></mspace> <msup><mrow><mtext>s</mtext></mrow> <mrow><mn>1</mn> <mo>/</mo> <mn>2</mn></mrow> </msup> </math> -range noise floor that varies with the MW carrier frequency and the detection frequency of the pulse sequence. The data are described by a frequency-domain model incorporating the MW phase-noise spectrum and the filter-function response of the sensing protocol. For controlled injection of white and random-walk phase noise, the observed NV magnetic noise floor is described by simple analytic expressions that accurately capture the scaling with pulse sequence length and the number of <math><mi>π</mi></math> pulses. We outline several strategies to suppress the impact of MW phase noise and implement a version, based on gradiometry, that realizes a > 10-fold suppression. Our study highlights an important challenge in the pursuit of sensitive diamond quantum sensors and is applicable to other qubit systems with a large transition frequency.</p>","PeriodicalId":520315,"journal":{"name":"Physical review research","volume":"6 4","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12524190/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145310577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}