Pub Date : 2023-11-13DOI: 10.1103/physreva.108.053314
Sibo Guo, Juntao Huang, Jiangping Hu, Zi-Xiang Li
A programmable quantum simulator using Rydberg-atom array provides a promising route to demystifying quantum many-body physics in strongly correlated systems. Motivated by the recent realization of various quantum magnetic phases on the frustrated Rydberg-atom array, we perform numerically exact quantum Monte Carlo simulations to investigate the exotic states of matter emerging in the model describing the Rydberg atom on a triangular lattice. Our state-of-the-art simulation unveils the $sqrt{3}ifmmodetimeselsetexttimesfi{}sqrt{3}$ triangular antiferromagnetic order exists at $1/3$ or $2/3$-Rydberg filling, consistent with the observation in experiments. Remarkably, $sqrt{3}ifmmodetimeselsetexttimesfi{}sqrt{3}$ long-range order arising from order-by-disorder mechanism emerges at $1/2$ filling. At finite temperature, $mathrm{U}(1)$ symmetry is emergent at $1/2$ filling and a Kosterlitz-Thouless phase transition occurs with increasing temperature. These intriguing phenomena are potentially detected in future Rydberg-atom experiments.
{"title":"Order by disorder and an emergent Kosterlitz-Thouless phase in a triangular Rydberg array","authors":"Sibo Guo, Juntao Huang, Jiangping Hu, Zi-Xiang Li","doi":"10.1103/physreva.108.053314","DOIUrl":"https://doi.org/10.1103/physreva.108.053314","url":null,"abstract":"A programmable quantum simulator using Rydberg-atom array provides a promising route to demystifying quantum many-body physics in strongly correlated systems. Motivated by the recent realization of various quantum magnetic phases on the frustrated Rydberg-atom array, we perform numerically exact quantum Monte Carlo simulations to investigate the exotic states of matter emerging in the model describing the Rydberg atom on a triangular lattice. Our state-of-the-art simulation unveils the $sqrt{3}ifmmodetimeselsetexttimesfi{}sqrt{3}$ triangular antiferromagnetic order exists at $1/3$ or $2/3$-Rydberg filling, consistent with the observation in experiments. Remarkably, $sqrt{3}ifmmodetimeselsetexttimesfi{}sqrt{3}$ long-range order arising from order-by-disorder mechanism emerges at $1/2$ filling. At finite temperature, $mathrm{U}(1)$ symmetry is emergent at $1/2$ filling and a Kosterlitz-Thouless phase transition occurs with increasing temperature. These intriguing phenomena are potentially detected in future Rydberg-atom experiments.","PeriodicalId":20121,"journal":{"name":"Physical Review","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136282867","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}
Pub Date : 2023-11-13DOI: 10.1103/physreva.108.052606
Weining Liu, Yisen Wang, Hailu Luo
In the standard weak measurement, the imaginary part of the weak value is usually constructed with a specific pre- or postselection state to cause a large shift of the frequency-domain pointer. In this paper we demonstrate that the purely real weak value can also shift the frequency-domain pointer when using a broad-spectrum light source. The reason for the deflection of the frequency-domain pointer in this scheme is that the postselection probability of different frequency is different, which causes the rearrangement of the amplitudes of the spectrum. The weak measurement with real weak value can be used for the estimation of time delay, and it is found that it can reach the same high resolution as the standard weak measurement in some sensitive regions.
{"title":"Precision estimation of time delay based on weak measurement with real weak value","authors":"Weining Liu, Yisen Wang, Hailu Luo","doi":"10.1103/physreva.108.052606","DOIUrl":"https://doi.org/10.1103/physreva.108.052606","url":null,"abstract":"In the standard weak measurement, the imaginary part of the weak value is usually constructed with a specific pre- or postselection state to cause a large shift of the frequency-domain pointer. In this paper we demonstrate that the purely real weak value can also shift the frequency-domain pointer when using a broad-spectrum light source. The reason for the deflection of the frequency-domain pointer in this scheme is that the postselection probability of different frequency is different, which causes the rearrangement of the amplitudes of the spectrum. The weak measurement with real weak value can be used for the estimation of time delay, and it is found that it can reach the same high resolution as the standard weak measurement in some sensitive regions.","PeriodicalId":20121,"journal":{"name":"Physical Review","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136282872","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}
Pub Date : 2023-11-13DOI: 10.1103/physreva.108.l051701
A. Kudlis, D. Novokreschenov, I. Iorsh, I. V. Tokatly
The authors quantitatively describe the nonperturbative correlations in finite- size cavity quantum electrodynamics (cavity QED) systems. They track the onset of these correlations as the system departs from the thermodynamic limit. They propose an experimental setup, where these correlations can be directly probed.
{"title":"Nonperturbative effects of deep strong light-matter interaction in a mesoscopic cavity-QED system","authors":"A. Kudlis, D. Novokreschenov, I. Iorsh, I. V. Tokatly","doi":"10.1103/physreva.108.l051701","DOIUrl":"https://doi.org/10.1103/physreva.108.l051701","url":null,"abstract":"The authors quantitatively describe the nonperturbative correlations in finite- size cavity quantum electrodynamics (cavity QED) systems. They track the onset of these correlations as the system departs from the thermodynamic limit. They propose an experimental setup, where these correlations can be directly probed.","PeriodicalId":20121,"journal":{"name":"Physical Review","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136283635","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}
Pub Date : 2023-11-13DOI: 10.1103/physreve.108.054120
Jonathan Lee Mace, Travis B. Peery, Scott W. Teare
A level frequency postulate is proposed in the context of the Onsager regression hypothesis, and is utilized to demonstrate Fourier fluctuation time between levels in an analog system composed of red and white dice. This dice system is shown to be analogous to an isolated composite system of particles through derivation of the level probability distribution. Level fluctuation time is developed as an algebraic expression involving average energy and a Gaussian parameter, with quasistatic evolution demonstrated as an integral over fluctuation time.
{"title":"Level frequency postulate and the dice analog","authors":"Jonathan Lee Mace, Travis B. Peery, Scott W. Teare","doi":"10.1103/physreve.108.054120","DOIUrl":"https://doi.org/10.1103/physreve.108.054120","url":null,"abstract":"A level frequency postulate is proposed in the context of the Onsager regression hypothesis, and is utilized to demonstrate Fourier fluctuation time between levels in an analog system composed of red and white dice. This dice system is shown to be analogous to an isolated composite system of particles through derivation of the level probability distribution. Level fluctuation time is developed as an algebraic expression involving average energy and a Gaussian parameter, with quasistatic evolution demonstrated as an integral over fluctuation time.","PeriodicalId":20121,"journal":{"name":"Physical Review","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136283970","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}
Pub Date : 2023-11-13DOI: 10.1103/physreva.108.052810
Mao-Rui Cai, Chong Ye, Yong Li, Hui Dong
Developing effective methods to measure the enantiomeric excess of chiral mixtures is one of the major topics in chiral molecular research but remains challenging. An enantiodetection method via two-dimensional (2D) spectroscopy based on a four-level model containing a cyclic three-level system (CTLS) of chiral molecules was recently proposed and demonstrated, but with a strict condition of one-photon resonance (where three driving fields are exactly resonantly coupled to the three electric dipole transitions) in the CTLS and narrow-band probe-pulse assumption. Here, we extend the 2D spectroscopy method to more general experimental conditions, with three-photon resonance (where the sum of the two smaller frequencies among the three driving fields equals the third one) and a broadband probe pulse. Our method remains effective on enantiodetection with the help of experimental techniques such as the chop-detection method, which is used to eliminate the influence of the other redundant levels that exist in the real system of chiral molecules. Under these more general conditions, the enantiomeric excess of the chiral mixture is estimated by taking an easily available standard sample (usually the racemic mixture) as the reference.
{"title":"Enantiodetection via two-dimensional spectroscopy: Extending the methodology to general experimental conditions","authors":"Mao-Rui Cai, Chong Ye, Yong Li, Hui Dong","doi":"10.1103/physreva.108.052810","DOIUrl":"https://doi.org/10.1103/physreva.108.052810","url":null,"abstract":"Developing effective methods to measure the enantiomeric excess of chiral mixtures is one of the major topics in chiral molecular research but remains challenging. An enantiodetection method via two-dimensional (2D) spectroscopy based on a four-level model containing a cyclic three-level system (CTLS) of chiral molecules was recently proposed and demonstrated, but with a strict condition of one-photon resonance (where three driving fields are exactly resonantly coupled to the three electric dipole transitions) in the CTLS and narrow-band probe-pulse assumption. Here, we extend the 2D spectroscopy method to more general experimental conditions, with three-photon resonance (where the sum of the two smaller frequencies among the three driving fields equals the third one) and a broadband probe pulse. Our method remains effective on enantiodetection with the help of experimental techniques such as the chop-detection method, which is used to eliminate the influence of the other redundant levels that exist in the real system of chiral molecules. Under these more general conditions, the enantiomeric excess of the chiral mixture is estimated by taking an easily available standard sample (usually the racemic mixture) as the reference.","PeriodicalId":20121,"journal":{"name":"Physical Review","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136348610","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}
Pub Date : 2023-11-13DOI: 10.1103/physreve.108.054308
Lena Mangold, Camille Roth
A myriad of approaches have been proposed to characterize the mesoscale structure of networks most often as a partition based on patterns variously called communities, blocks, or clusters. Clearly, distinct methods designed to detect different types of patterns may provide a variety of answers' to the networks mesoscale structure. Yet even multiple runs of a given method can sometimes yield diverse and conflicting results, producing entire landscapes of partitions which potentially include multiple (locally optimal) mesoscale explanations of the network. Such ambiguity motivates a closer look at the ability of these methods to find multiple qualitatively different ``ground truth'' partitions in a network. Here we propose the stochastic cross-block model (SCBM), a generative model which allows for two distinct partitions to be built into the mesoscale structure of a single benchmark network. We demonstrate a use case of the benchmark model by appraising the power of stochastic block models (SBMs) to detect implicitly planted coexisting bicommunity and core-periphery structures of different strengths. Given our model design and experimental setup, we find that the ability to detect the two partitions individually varies by SBM variant and that coexistence of both partitions is recovered only in a very limited number of cases. Our findings suggest that in most instances only one---in some way dominating---structure can be detected, even in the presence of other partitions. They underline the need for considering entire landscapes of partitions when different competing explanations exist and motivate future research to advance partition coexistence detection methods. Our model also contributes to the field of benchmark networks more generally by enabling further exploration of the ability of new and existing methods to detect ambiguity in the mesoscale structure of networks.
{"title":"Generative models for two-ground-truth partitions in networks","authors":"Lena Mangold, Camille Roth","doi":"10.1103/physreve.108.054308","DOIUrl":"https://doi.org/10.1103/physreve.108.054308","url":null,"abstract":"A myriad of approaches have been proposed to characterize the mesoscale structure of networks most often as a partition based on patterns variously called communities, blocks, or clusters. Clearly, distinct methods designed to detect different types of patterns may provide a variety of answers' to the networks mesoscale structure. Yet even multiple runs of a given method can sometimes yield diverse and conflicting results, producing entire landscapes of partitions which potentially include multiple (locally optimal) mesoscale explanations of the network. Such ambiguity motivates a closer look at the ability of these methods to find multiple qualitatively different ``ground truth'' partitions in a network. Here we propose the stochastic cross-block model (SCBM), a generative model which allows for two distinct partitions to be built into the mesoscale structure of a single benchmark network. We demonstrate a use case of the benchmark model by appraising the power of stochastic block models (SBMs) to detect implicitly planted coexisting bicommunity and core-periphery structures of different strengths. Given our model design and experimental setup, we find that the ability to detect the two partitions individually varies by SBM variant and that coexistence of both partitions is recovered only in a very limited number of cases. Our findings suggest that in most instances only one---in some way dominating---structure can be detected, even in the presence of other partitions. They underline the need for considering entire landscapes of partitions when different competing explanations exist and motivate future research to advance partition coexistence detection methods. Our model also contributes to the field of benchmark networks more generally by enabling further exploration of the ability of new and existing methods to detect ambiguity in the mesoscale structure of networks.","PeriodicalId":20121,"journal":{"name":"Physical Review","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136282657","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}
Pub Date : 2023-11-13DOI: 10.1103/physreva.108.052410
Salini Rajeev, Mayukh Lahiri
Conventional methods of measuring entanglement in a two-qubit photonic mixed state require detection of both qubits. We generalize a recently introduced method which does not require detection of both qubits, by extending it to cover a wider class of entangled states. Specifically, we present a detailed theory that shows how to measure entanglement in a family of two-qubit mixed states, obtained by generalizing Werner states, without detecting one of the qubits. Our method is interferometric and does not require any coincidence measurement or postselection. We also perform a quantitative analysis of anticipated experimental imperfections. We show that the method is resistant to a decrease in the interference visibility resulting from such imperfections.
{"title":"Single-qubit measurement of two-qubit entanglement in generalized Werner states","authors":"Salini Rajeev, Mayukh Lahiri","doi":"10.1103/physreva.108.052410","DOIUrl":"https://doi.org/10.1103/physreva.108.052410","url":null,"abstract":"Conventional methods of measuring entanglement in a two-qubit photonic mixed state require detection of both qubits. We generalize a recently introduced method which does not require detection of both qubits, by extending it to cover a wider class of entangled states. Specifically, we present a detailed theory that shows how to measure entanglement in a family of two-qubit mixed states, obtained by generalizing Werner states, without detecting one of the qubits. Our method is interferometric and does not require any coincidence measurement or postselection. We also perform a quantitative analysis of anticipated experimental imperfections. We show that the method is resistant to a decrease in the interference visibility resulting from such imperfections.","PeriodicalId":20121,"journal":{"name":"Physical Review","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136282679","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}
Pub Date : 2023-11-09DOI: 10.1103/physreve.108.054701
Piotr Kubala, Michał Cieśla, Lech Longa
The main objective of this work is to clarify the role that taper-shaped elongated molecules, i.e., molecules with one end wider than the other, can play in stabilizing orientational order. The focus is exclusively on entropy-driven self-organization induced by purely excluded volume interactions. Drawing an analogy to RM734 (4-[(4-nitrophenoxy)carbonyl]phenyl-2,4-dimethoxybenzoate), which is known to stabilize ferroelectric nematic (${text{N}}_{text{F}}$) and nematic splay (${text{N}}_{text{S}}$) phases, and assuming that molecular biaxiality is of secondary importance, we consider monodisperse systems composed of hard molecules. Each molecule is modeled using six collinear tangent spheres with linearly decreasing diameters. Through hard-particle, constant-pressure Monte Carlo simulations, we study the emergent phases as functions of the ratio between the smallest and largest diameters of the spheres (denoted as $d$) and the packing fraction ($ensuremath{eta}$). To analyze global and local molecular orderings, we examine molecular configurations in terms of nematic, smectic, and hexatic order parameters. Additionally, we investigate the radial pair distribution function, polarization correlation function, and the histogram of angles between molecular axes. The last characteristic is utilized to quantify local splay. The findings reveal that splay-induced deformations drive unusual long-range orientational order at relatively high packing fractions ($ensuremath{eta}>0.5$), corresponding to crystalline phases. When $ensuremath{eta}<0.5$, only short-range order is affected, and in addition to the isotropic liquid, only the standard nematic and smectic-A liquid crystalline phases are stabilized. However, for $ensuremath{eta}>0.5$, apart from the ordinary nonpolar hexagonal crystal, three additional frustrated crystalline polar blue phases with long-range splay modulation are observed: antiferroelectric splay crystal (${text{Cr}}_{text{S}}{text{P}}_{text{A}}$), antiferroelectric double-splay crystal (${text{Cr}}_{text{DS}}{text{P}}_{text{A}}$), and ferroelectric double-splay crystal (${text{Cr}}_{text{DS}}{text{P}}_{text{F}}$). Finally, we employ Onsager-Parsons-Lee local density functional theory to investigate whether any sterically induced (anti)ferroelectric nematic or smectic-A type of ordering is possible for our system, at least in a metastable regime.
{"title":"Splay-induced order in systems of hard tapers","authors":"Piotr Kubala, Michał Cieśla, Lech Longa","doi":"10.1103/physreve.108.054701","DOIUrl":"https://doi.org/10.1103/physreve.108.054701","url":null,"abstract":"The main objective of this work is to clarify the role that taper-shaped elongated molecules, i.e., molecules with one end wider than the other, can play in stabilizing orientational order. The focus is exclusively on entropy-driven self-organization induced by purely excluded volume interactions. Drawing an analogy to RM734 (4-[(4-nitrophenoxy)carbonyl]phenyl-2,4-dimethoxybenzoate), which is known to stabilize ferroelectric nematic (${text{N}}_{text{F}}$) and nematic splay (${text{N}}_{text{S}}$) phases, and assuming that molecular biaxiality is of secondary importance, we consider monodisperse systems composed of hard molecules. Each molecule is modeled using six collinear tangent spheres with linearly decreasing diameters. Through hard-particle, constant-pressure Monte Carlo simulations, we study the emergent phases as functions of the ratio between the smallest and largest diameters of the spheres (denoted as $d$) and the packing fraction ($ensuremath{eta}$). To analyze global and local molecular orderings, we examine molecular configurations in terms of nematic, smectic, and hexatic order parameters. Additionally, we investigate the radial pair distribution function, polarization correlation function, and the histogram of angles between molecular axes. The last characteristic is utilized to quantify local splay. The findings reveal that splay-induced deformations drive unusual long-range orientational order at relatively high packing fractions ($ensuremath{eta}>0.5$), corresponding to crystalline phases. When $ensuremath{eta}<0.5$, only short-range order is affected, and in addition to the isotropic liquid, only the standard nematic and smectic-A liquid crystalline phases are stabilized. However, for $ensuremath{eta}>0.5$, apart from the ordinary nonpolar hexagonal crystal, three additional frustrated crystalline polar blue phases with long-range splay modulation are observed: antiferroelectric splay crystal (${text{Cr}}_{text{S}}{text{P}}_{text{A}}$), antiferroelectric double-splay crystal (${text{Cr}}_{text{DS}}{text{P}}_{text{A}}$), and ferroelectric double-splay crystal (${text{Cr}}_{text{DS}}{text{P}}_{text{F}}$). Finally, we employ Onsager-Parsons-Lee local density functional theory to investigate whether any sterically induced (anti)ferroelectric nematic or smectic-A type of ordering is possible for our system, at least in a metastable regime.","PeriodicalId":20121,"journal":{"name":"Physical Review","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135290904","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}
Pub Date : 2023-11-09DOI: 10.1103/physreve.108.055303
Rongyan Yin, Qizhi Teng, Xiaohong Wu, Fan Zhang, Shuhua Xiong
Reconstruction of microstructure in granular porous media, which can be viewed as granular assemblies, is crucial for studying their characteristics and physical properties in various fields concerned with the behavior of such media, including petroleum geology and computational materials science. In spite of the fact that many existing studies have investigated grain reconstruction, most of them treat grains as simplified individuals for discrete reconstruction, which cannot replicate the complex geometrical shapes and natural interactions between grains. In this work, a hybrid generative model based on a deep-learning algorithm is proposed for high-quality three-dimensional (3D) microstructure reconstruction of granular porous media from a single two-dimensional (2D) slice image. The method extracts 2D prior information from the given image and generates the grain set as a whole. Both a self-attention module and effective pattern loss are introduced in a bid to enhance the reconstruction ability of the model. Samples with grains of varied geometrical shapes are utilized for the validation of our method, and experimental results demonstrate that our proposed approach can accurately reproduce the complex morphology and spatial distribution of grains without any artificiality. Furthermore, once the model training is complete, rapid end-to-end generation of diverse 3D realizations from a single 2D image can be achieved.
{"title":"Three-dimensional reconstruction of granular porous media based on deep generative models","authors":"Rongyan Yin, Qizhi Teng, Xiaohong Wu, Fan Zhang, Shuhua Xiong","doi":"10.1103/physreve.108.055303","DOIUrl":"https://doi.org/10.1103/physreve.108.055303","url":null,"abstract":"Reconstruction of microstructure in granular porous media, which can be viewed as granular assemblies, is crucial for studying their characteristics and physical properties in various fields concerned with the behavior of such media, including petroleum geology and computational materials science. In spite of the fact that many existing studies have investigated grain reconstruction, most of them treat grains as simplified individuals for discrete reconstruction, which cannot replicate the complex geometrical shapes and natural interactions between grains. In this work, a hybrid generative model based on a deep-learning algorithm is proposed for high-quality three-dimensional (3D) microstructure reconstruction of granular porous media from a single two-dimensional (2D) slice image. The method extracts 2D prior information from the given image and generates the grain set as a whole. Both a self-attention module and effective pattern loss are introduced in a bid to enhance the reconstruction ability of the model. Samples with grains of varied geometrical shapes are utilized for the validation of our method, and experimental results demonstrate that our proposed approach can accurately reproduce the complex morphology and spatial distribution of grains without any artificiality. Furthermore, once the model training is complete, rapid end-to-end generation of diverse 3D realizations from a single 2D image can be achieved.","PeriodicalId":20121,"journal":{"name":"Physical Review","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135291161","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}
Pub Date : 2023-11-09DOI: 10.1103/physreve.108.054404
Federico W. Pasini, Alexandra N. Busch, Ján Mináč, Krishnan Padmanabhan, Lyle Muller
Although temporal coding through spike-time patterns has long been of interest in neuroscience, the specific structures that could be useful for spike-time codes remain highly unclear. Here, we introduce an analytical approach, using techniques from discrete mathematics, to study spike-time codes. As an initial example, we focus on the phenomenon of ``phase precession'' in the rodent hippocampus. During navigation and learning on a physical track, specific cells in a rodent's brain form a highly structured pattern relative to the oscillation of population activity in this region. Studies of phase precession largely focus on its role in precisely ordering spike times for synaptic plasticity, as the role of phase precession in memory formation is well established. Comparatively less attention has been paid to the fact that phase precession represents one of the best candidates for a spike-time neural code. The precise nature of this code remains an open question. Here, we derive an analytical expression for a function mapping points in physical space to complex-valued spikes by representing individual spike times as complex numbers. The properties of this function make explicit a specific relationship between past and future in spike patterns of the hippocampus. Importantly, this mathematical approach generalizes beyond the specific phenomenon studied here, providing a technique to study the neural codes within precise spike-time sequences found during sensory coding and motor behavior. We then introduce a spike-based decoding algorithm, based on this function, that successfully decodes a simulated animal's trajectory using only the animal's initial position and a pattern of spike times. This decoder is robust to noise in spike times and works on a timescale almost an order of magnitude shorter than typically used with decoders that work on average firing rate. These results illustrate the utility of a discrete approach, based on the structure and symmetries in spike patterns across finite sets of cells, to provide insight into the structure and function of neural systems.
{"title":"Algebraic approach to spike-time neural codes in the hippocampus","authors":"Federico W. Pasini, Alexandra N. Busch, Ján Mináč, Krishnan Padmanabhan, Lyle Muller","doi":"10.1103/physreve.108.054404","DOIUrl":"https://doi.org/10.1103/physreve.108.054404","url":null,"abstract":"Although temporal coding through spike-time patterns has long been of interest in neuroscience, the specific structures that could be useful for spike-time codes remain highly unclear. Here, we introduce an analytical approach, using techniques from discrete mathematics, to study spike-time codes. As an initial example, we focus on the phenomenon of ``phase precession'' in the rodent hippocampus. During navigation and learning on a physical track, specific cells in a rodent's brain form a highly structured pattern relative to the oscillation of population activity in this region. Studies of phase precession largely focus on its role in precisely ordering spike times for synaptic plasticity, as the role of phase precession in memory formation is well established. Comparatively less attention has been paid to the fact that phase precession represents one of the best candidates for a spike-time neural code. The precise nature of this code remains an open question. Here, we derive an analytical expression for a function mapping points in physical space to complex-valued spikes by representing individual spike times as complex numbers. The properties of this function make explicit a specific relationship between past and future in spike patterns of the hippocampus. Importantly, this mathematical approach generalizes beyond the specific phenomenon studied here, providing a technique to study the neural codes within precise spike-time sequences found during sensory coding and motor behavior. We then introduce a spike-based decoding algorithm, based on this function, that successfully decodes a simulated animal's trajectory using only the animal's initial position and a pattern of spike times. This decoder is robust to noise in spike times and works on a timescale almost an order of magnitude shorter than typically used with decoders that work on average firing rate. These results illustrate the utility of a discrete approach, based on the structure and symmetries in spike patterns across finite sets of cells, to provide insight into the structure and function of neural systems.","PeriodicalId":20121,"journal":{"name":"Physical Review","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135240829","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}
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