Pub Date : 2024-07-03DOI: 10.1088/1361-6382/ad5826
Geoffrey Compère, Sk Jahanur Hoque and Emine Şeyma Kutluk
We obtain the closed form expression for the metric perturbation around de Sitter spacetime generated by a matter source below Hubble scale both in generalized harmonic gauge and in Bondi gauge up to quadrupolar order in the multipolar expansion, including both parities (i.e. both mass and current quadrupoles). We demonstrate that such a source causes a displacement memory effect close to future infinity that originates, in the even-parity sector, from a Λ-BMS transition between the two non-radiative regions of future infinity.
{"title":"Quadrupolar radiation in de Sitter: displacement memory and Bondi metric","authors":"Geoffrey Compère, Sk Jahanur Hoque and Emine Şeyma Kutluk","doi":"10.1088/1361-6382/ad5826","DOIUrl":"https://doi.org/10.1088/1361-6382/ad5826","url":null,"abstract":"We obtain the closed form expression for the metric perturbation around de Sitter spacetime generated by a matter source below Hubble scale both in generalized harmonic gauge and in Bondi gauge up to quadrupolar order in the multipolar expansion, including both parities (i.e. both mass and current quadrupoles). We demonstrate that such a source causes a displacement memory effect close to future infinity that originates, in the even-parity sector, from a Λ-BMS transition between the two non-radiative regions of future infinity.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141521463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.1007/s11182-024-03217-x
E. Çopuroğlu, D. Özgül
Thermoelectric materials are of growing interest to renewable energy technologies and applications. Because of the work progress of thermoelectric materials, experimental and theoretical methods in evaluating thermodynamic behavior and properties of these materials play a significant role. As is known, heat capacity is one of the fundamental thermodynamic properties of thermoelectric materials that should be foreseen accurately. The Debye–Einstein approximation is one of the efficient methods for calculating the heat capacity of materials without any restriction in their use. For this purpose, this work aims at the heat capacity calculation of PbTe, PbS and PbSe thermoelectric materials using the Debye–Einstein approximation.
{"title":"Theoretical Investigation for Interpreting Heat Capacity of Thermoelectric Materials Using Debye–Einstein Approximation","authors":"E. Çopuroğlu, D. Özgül","doi":"10.1007/s11182-024-03217-x","DOIUrl":"https://doi.org/10.1007/s11182-024-03217-x","url":null,"abstract":"<p>Thermoelectric materials are of growing interest to renewable energy technologies and applications. Because of the work progress of thermoelectric materials, experimental and theoretical methods in evaluating thermodynamic behavior and properties of these materials play a significant role. As is known, heat capacity is one of the fundamental thermodynamic properties of thermoelectric materials that should be foreseen accurately. The Debye–Einstein approximation is one of the efficient methods for calculating the heat capacity of materials without any restriction in their use. For this purpose, this work aims at the heat capacity calculation of PbTe, PbS and PbSe thermoelectric materials using the Debye–Einstein approximation.</p>","PeriodicalId":770,"journal":{"name":"Russian Physics Journal","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141522753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.1103/physreve.110.014403
Martin Girard, Monica Olvera de la Cruz, John F. Marko, Aykut Erbaş
The highly and slightly condensed forms of chromatin, heterochromatin and euchromatin, respectively, segregate in the cell nucleus. Heterochromatin is more abundant in the nucleus periphery. Here we study the mechanism of heterochromatin segregation by modeling interphase chromosomes as diblock ring copolymers confined in a rigid spherical shell using molecular dynamics simulations. In our model, heterochromatin and euchromatin are distinguished by their bending stiffnesses only, while an interaction potential between the spherical shell and chromatin is used to model lamin-associated proteins. Our simulations indicate that in the absence of attractive interactions between the nuclear shell and the chromatin, most heterochromatin segregates towards the nuclear interior due to the depletion of less flexible heterochromatin segments from the nuclear periphery. This inverted chromatin distribution,which is opposite to the conventional case with heterochromatin dominating at the periphery, is in accord with experimental observations in rod cells. This “inversion” is also found to be independent of the heterochromatin concentration and chromosome number. The chromatin distribution at the periphery found in vivo can be recovered by further increasing the bending stiffness of heterochromatin segments or by turning on attractive interactions between the nuclear shell and heterochromatin. Our results indicate that the bending stiffness of chromatin could be a contributor to chromosome organization along with differential effects of -driven phase segregation and of loop extruders and interactions with the nuclear envelope and topological constraints.
{"title":"Heterogeneous flexibility can contribute to chromatin segregation in the cell nucleus","authors":"Martin Girard, Monica Olvera de la Cruz, John F. Marko, Aykut Erbaş","doi":"10.1103/physreve.110.014403","DOIUrl":"https://doi.org/10.1103/physreve.110.014403","url":null,"abstract":"The highly and slightly condensed forms of chromatin, heterochromatin and euchromatin, respectively, segregate in the cell nucleus. Heterochromatin is more abundant in the nucleus periphery. Here we study the mechanism of heterochromatin segregation by modeling interphase chromosomes as diblock ring copolymers confined in a rigid spherical shell using molecular dynamics simulations. In our model, heterochromatin and euchromatin are distinguished by their bending stiffnesses only, while an interaction potential between the spherical shell and chromatin is used to model lamin-associated proteins. Our simulations indicate that in the absence of attractive interactions between the nuclear shell and the chromatin, most heterochromatin segregates towards the nuclear interior due to the depletion of less flexible heterochromatin segments from the nuclear periphery. This inverted chromatin distribution,which is opposite to the conventional case with heterochromatin dominating at the periphery, is in accord with experimental observations in rod cells. This “inversion” is also found to be independent of the heterochromatin concentration and chromosome number. The chromatin distribution at the periphery found <i>in vivo</i> can be recovered by further increasing the bending stiffness of heterochromatin segments or by turning on attractive interactions between the nuclear shell and heterochromatin. Our results indicate that the bending stiffness of chromatin could be a contributor to chromosome organization along with differential effects of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mrow><mi>HP</mi><mn>1</mn></mrow><mi>α</mi></mrow></math>-driven phase segregation and of loop extruders and interactions with the nuclear envelope and topological constraints.","PeriodicalId":20085,"journal":{"name":"Physical review. E","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141526292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.1103/physrevb.110.045407
J. Rika Simon, Dmitrii Maksimov, Christian Lotze, Paul Wiechers, Juan Pablo Guerrero Felipe, Björn Kobin, Jutta Schwarz, Stefan Hecht, Katharina J. Franke, Mariana Rossi
Sulfur vacancies in on Au(111) have been shown to be negatively charged as reflected by a Kondo resonance. Here, we use scanning tunneling microscopy to show that these vacancies serve as anchoring sites for thiol-based molecules with two distinct reaction products, one of them showing a Kondo resonance. Based on comparisons with density-functional theory (DFT) calculations, including a random structure search and computation of energies and electronic properties at a hybrid exchange-correlation functional level, we conclude that both anchored molecules are charge neutral. We propose that one of them is an anchored intact molecule while the other one is the result of catalytically activated dehydrogenation to with subsequent anchoring. Our investigations highlight a perspective of functionalizing defects with thiol-terminated molecules that can be equipped with additional functional groups, such as charge donor or acceptor moieties, switching units, or magnetic centers.
{"title":"Atomic-scale perspective on individual thiol-terminated molecules anchored to single S vacancies in MoS2","authors":"J. Rika Simon, Dmitrii Maksimov, Christian Lotze, Paul Wiechers, Juan Pablo Guerrero Felipe, Björn Kobin, Jutta Schwarz, Stefan Hecht, Katharina J. Franke, Mariana Rossi","doi":"10.1103/physrevb.110.045407","DOIUrl":"https://doi.org/10.1103/physrevb.110.045407","url":null,"abstract":"Sulfur vacancies in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>MoS</mi><mn>2</mn></msub></math> on Au(111) have been shown to be negatively charged as reflected by a Kondo resonance. Here, we use scanning tunneling microscopy to show that these vacancies serve as anchoring sites for thiol-based molecules <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>(</mo><msub><mi>CF</mi><mn>3</mn></msub><mtext>−</mtext><mn>3</mn><mi mathvariant=\"normal\">P</mi><mtext>−</mtext><mi>SH</mi><mo>)</mo></mrow></math> with two distinct reaction products, one of them showing a Kondo resonance. Based on comparisons with density-functional theory (DFT) calculations, including a random structure search and computation of energies and electronic properties at a hybrid exchange-correlation functional level, we conclude that both anchored molecules are charge neutral. We propose that one of them is an anchored intact <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>CF</mi><mn>3</mn></msub><mtext>−</mtext><mn>3</mn><mi mathvariant=\"normal\">P</mi><mtext>−</mtext><mi>SH</mi></mrow></math> molecule while the other one is the result of catalytically activated dehydrogenation to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>CF</mi><mn>3</mn></msub><mtext>−</mtext><mn>3</mn><mi mathvariant=\"normal\">P</mi><mtext>−</mtext><mi mathvariant=\"normal\">S</mi></mrow></math> with subsequent anchoring. Our investigations highlight a perspective of functionalizing defects with thiol-terminated molecules that can be equipped with additional functional groups, such as charge donor or acceptor moieties, switching units, or magnetic centers.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.1103/physrevb.110.024502
Chunxiao Liu, Shubhayu Chatterjee, Thomas Scaffidi, Erez Berg, Ehud Altman
A recent experiment on the bulk compound reveals an unusual time-reversal symmetry-breaking superconducting state that possesses a magnetic memory not manifest in the normal state. Here we provide a mechanism for this observation by studying the magnetic and electronic properties of . We discuss the criterion for a small magnetization in the normal state in terms of spin and orbital magnetizations. Based on an analysis of lattice symmetry and Fermi surface structure, we propose that realizes superconductivity in the interlayer, equal-spin channel with a gap function whose phase winds along the Fermi surface by an integer multiple of . The enhancement of the magnetization in the superconducting state compared to the normal state can be explained if the state with a gap winding of is realized, accounting for the observed magnetic memory. We discuss how this superconducting state can be probed experimentally by spin-polarized scanning tunneling microscopy.
{"title":"Magnetization amplification in the interlayer pairing superconductor 4Hb−TaS2","authors":"Chunxiao Liu, Shubhayu Chatterjee, Thomas Scaffidi, Erez Berg, Ehud Altman","doi":"10.1103/physrevb.110.024502","DOIUrl":"https://doi.org/10.1103/physrevb.110.024502","url":null,"abstract":"A recent experiment on the bulk compound <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>4</mn><mrow><mi>H</mi><mi>b</mi></mrow><mtext>−</mtext><msub><mi>TaS</mi><mn>2</mn></msub></mrow></math> reveals an unusual time-reversal symmetry-breaking superconducting state that possesses a magnetic memory not manifest in the normal state. Here we provide a mechanism for this observation by studying the magnetic and electronic properties of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>4</mn><mrow><mi>H</mi><mi>b</mi></mrow><mtext>−</mtext><msub><mi>TaS</mi><mn>2</mn></msub></mrow></math>. We discuss the criterion for a small magnetization in the normal state in terms of spin and orbital magnetizations. Based on an analysis of lattice symmetry and Fermi surface structure, we propose that <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>4</mn><mrow><mi>H</mi><mi>b</mi></mrow><mtext>−</mtext><msub><mi>TaS</mi><mn>2</mn></msub></mrow></math> realizes superconductivity in the interlayer, equal-spin channel with a gap function whose phase winds along the Fermi surface by an integer multiple of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>6</mn><mi>π</mi></mrow></math>. The enhancement of the magnetization in the superconducting state compared to the normal state can be explained if the state with a gap winding of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>6</mn><mi>π</mi></mrow></math> is realized, accounting for the observed magnetic memory. We discuss how this superconducting state can be probed experimentally by spin-polarized scanning tunneling microscopy.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.1103/physrevc.110.014311
J. Khuyagbaatar
The most probable outcome of ternary fission is the emission of two heavy fragments and one light charged particle. In about 90% of cases, these are particles, which often referred to aslong-range alpha (LRA). Such decay has been extensively studied over decades in various heavy fissioning systems. The probability of such a process has been found to be about relative to binary fission. The experimental data showed an increasing trend in the probability of such a process with an increase in fissility parameter within the range of 35–39. In recent decades, a region of the heaviest nuclei has been substantially expanded in both proton and neutron numbers. This includes neutron-deficient heavy and superheavy nuclei with fissility parameters, which are significantly exceeding the aforementioned range. In the present work, the currently available experimental data on the probability of the LRA emission, which is a representative of ternary fission, are discussed. The probabilities of LRA emission were calculated within the various empirical approaches, including the presently suggested semiempirical expression. The latter one was derived on the basis of the -decay property of the fissioning nucleus. The results of all approaches discussed show that the probabilities of LRA emission are substantial (up to a percentage) in the fission of neutron-deficient heavy and superheavy nuclei.
{"title":"Ternary fission with the emission of long-range α particles in fission of the heaviest nuclei","authors":"J. Khuyagbaatar","doi":"10.1103/physrevc.110.014311","DOIUrl":"https://doi.org/10.1103/physrevc.110.014311","url":null,"abstract":"The most probable outcome of ternary fission is the emission of two heavy fragments and one light charged particle. In about 90% of cases, these are <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>α</mi></math> particles, which often referred to aslong-range alpha (LRA). Such decay has been extensively studied over decades in various heavy fissioning systems. The probability of such a process has been found to be about <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mrow><mo>(</mo><mn>2</mn><mo>–</mo><mn>4</mn><mo>)</mo></mrow><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math> relative to binary fission. The experimental data showed an increasing trend in the probability of such a process with an increase in fissility parameter within the range of 35–39. In recent decades, a region of the heaviest nuclei has been substantially expanded in both proton and neutron numbers. This includes neutron-deficient heavy and superheavy nuclei with fissility parameters, which are significantly exceeding the aforementioned range. In the present work, the currently available experimental data on the probability of the LRA emission, which is a representative of ternary fission, are discussed. The probabilities of LRA emission were calculated within the various empirical approaches, including the presently suggested semiempirical expression. The latter one was derived on the basis of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>α</mi></math>-decay property of the fissioning nucleus. The results of all approaches discussed show that the probabilities of LRA emission are substantial (up to a percentage) in the fission of neutron-deficient heavy and superheavy nuclei.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
The crystal structure of organic semiconductors is an important factor that dominates various electronic properties, including charge transport properties. However, compared with the crystal structures of inorganic semiconductors, those of organic semiconductors are difficult to determine by powder x-ray diffraction (PXRD) analysis. Our proposed machine-learning (neural-network) technique can determine the diffraction peaks buried in noise and make deconvolution of the overlapped peaks of organic semiconductors, resulting in crystal-structure determination by the Rietveld analysis. As a demonstration, we apply the method to a few high-mobility organic semiconductors and confirm that the method is potentially useful for analyzing the crystal structure of organic semiconductors. The present method is also expected to be applicable to the determination of complex crystal structures in addition to organic semiconductors.
有机半导体的晶体结构是主导各种电子特性（包括电荷传输特性）的重要因素。然而，与无机半导体的晶体结构相比，有机半导体的晶体结构很难通过粉末 X 射线衍射（PXRD）分析来确定。我们提出的机器学习（神经网络）技术可以确定埋藏在噪声中的衍射峰，并对有机半导体的重叠峰进行解卷积，从而通过里特维尔德分析法确定晶体结构。作为示范，我们将该方法应用于几种高迁移率有机半导体，并证实该方法可用于分析有机半导体的晶体结构。除有机半导体外，本方法还有望适用于复杂晶体结构的测定。
{"title":"Powder x-ray diffraction analysis with machine learning for organic-semiconductor crystal-structure determination","authors":"Naoyuki Niitsu, Masato Mitani, Hiroyuki Ishii, Nobuhiko Kobayashi, Kenji Hirose, Shun Watanabe, Toshihiro Okamoto, Jun Takeya","doi":"10.1063/5.0208919","DOIUrl":"https://doi.org/10.1063/5.0208919","url":null,"abstract":"The crystal structure of organic semiconductors is an important factor that dominates various electronic properties, including charge transport properties. However, compared with the crystal structures of inorganic semiconductors, those of organic semiconductors are difficult to determine by powder x-ray diffraction (PXRD) analysis. Our proposed machine-learning (neural-network) technique can determine the diffraction peaks buried in noise and make deconvolution of the overlapped peaks of organic semiconductors, resulting in crystal-structure determination by the Rietveld analysis. As a demonstration, we apply the method to a few high-mobility organic semiconductors and confirm that the method is potentially useful for analyzing the crystal structure of organic semiconductors. The present method is also expected to be applicable to the determination of complex crystal structures in addition to organic semiconductors.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141521517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Ricardo Herrera Romero, Miguel Angel Bastarrachea-Magnani
Phase and amplitude modes, also called polariton modes, are emergent phenomena that manifest across diverse physical systems, from condensed matter and particle physics to quantum optics. We study their behavior in an anisotropic Dicke model that includes collective matter interactions. We study the low-lying spectrum in the thermodynamic limit via the Holstein–Primakoff transformation and contrast the results with the semi-classical energy surface obtained via coherent states. We also explore the geometric phase for both boson and spin contours in the parameter space as a function of the phases in the system. We unveil novel phenomena due to the unique critical features provided by the interplay between the anisotropy and matter interactions. We expect our results to serve the observation of phase and amplitude modes in current quantum information platforms.
{"title":"Phase and Amplitude Modes in the Anisotropic Dicke Model with Matter Interactions","authors":"Ricardo Herrera Romero, Miguel Angel Bastarrachea-Magnani","doi":"10.3390/e26070574","DOIUrl":"https://doi.org/10.3390/e26070574","url":null,"abstract":"Phase and amplitude modes, also called polariton modes, are emergent phenomena that manifest across diverse physical systems, from condensed matter and particle physics to quantum optics. We study their behavior in an anisotropic Dicke model that includes collective matter interactions. We study the low-lying spectrum in the thermodynamic limit via the Holstein–Primakoff transformation and contrast the results with the semi-classical energy surface obtained via coherent states. We also explore the geometric phase for both boson and spin contours in the parameter space as a function of the phases in the system. We unveil novel phenomena due to the unique critical features provided by the interplay between the anisotropy and matter interactions. We expect our results to serve the observation of phase and amplitude modes in current quantum information platforms.","PeriodicalId":11694,"journal":{"name":"Entropy","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141522001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.1103/physreve.110.014113
Francisco J. Sevilla, Adriano Valdés-Gómez, Alexis Torres-Carbajal
A model for anomalous transport of tracer particles diffusing in complex media in two dimensions is proposed. The model takes into account the characteristics of persistent motion that an active bath transfers to the tracer; thus, the model proposed here extends active Brownian motion, for which the stochastic dynamics of the orientation of the propelling force is described by scaled Brownian motion (sBm), identified by time-dependent diffusivity of the form . If , sBm is highly nonstationary and suitable to describe such nonequilibrium dynamics induced by complex media. In this paper, we provide analytical calculations and computer simulations to show that genuine anomalous diffusion emerges in the long-time regime, with a time scaling of the mean-squared displacement , while ballistic transport , characteristic of persistent motion, is found in the short-time regime. We also analyze the time dependence of the kurtosis, and the intermediate scattering function of the position distribution, as well as the propulsion autocorrelation function, which defines the effective persistence time.
{"title":"Anomalous diffusion of scaled Brownian tracers","authors":"Francisco J. Sevilla, Adriano Valdés-Gómez, Alexis Torres-Carbajal","doi":"10.1103/physreve.110.014113","DOIUrl":"https://doi.org/10.1103/physreve.110.014113","url":null,"abstract":"A model for anomalous transport of tracer particles diffusing in complex media in two dimensions is proposed. The model takes into account the characteristics of persistent motion that an active bath transfers to the tracer; thus, the model proposed here extends active Brownian motion, for which the stochastic dynamics of the orientation of the propelling force is described by scaled Brownian motion (sBm), identified by time-dependent diffusivity of the form <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>D</mi><mi>β</mi></msub><mo>∝</mo><msup><mi>t</mi><mrow><mi>β</mi><mo>−</mo><mn>1</mn></mrow></msup></mrow><mo>,</mo><mo> </mo><mrow><mi>β</mi><mo>></mo><mn>0</mn></mrow></math>. If <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>β</mi><mo>≠</mo><mn>1</mn></mrow></math>, sBm is highly nonstationary and suitable to describe such nonequilibrium dynamics induced by complex media. In this paper, we provide analytical calculations and computer simulations to show that genuine anomalous diffusion emerges in the long-time regime, with a time scaling of the mean-squared displacement <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>t</mi><mrow><mn>2</mn><mo>−</mo><mi>β</mi></mrow></msup></math>, while ballistic transport <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>t</mi><mn>2</mn></msup></math>, characteristic of persistent motion, is found in the short-time regime. We also analyze the time dependence of the kurtosis, and the intermediate scattering function of the position distribution, as well as the propulsion autocorrelation function, which defines the effective persistence time.","PeriodicalId":20085,"journal":{"name":"Physical review. E","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141526291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.1088/2058-9565/ad5a37
Siyuan Niu, Aida Todri-Sanial and Nicholas T Bronn
Dynamical decoupling (DD) is one of the simplest error suppression methods, aiming to enhance the coherence of qubits in open quantum systems. Moreover, DD has demonstrated effectiveness in reducing coherent crosstalk, one major error source in near-term quantum hardware, which manifests from two types of interactions. Static crosstalk exists in various hardware platforms, including superconductor and semiconductor qubits, by virtue of always-on qubit-qubit coupling. Additionally, driven crosstalk may occur as an unwanted drive term due to leakage from driven gates on other qubits. Here we explore a novel staggered DD protocol tailored for multi-qubit systems that suppresses the decoherence error and both types of coherent crosstalk. We develop two experimental setups—an ‘idle–idle’ experiment in which two pairs of qubits undergo free evolution simultaneously and a ‘driven-idle’ experiment in which one pair is continuously driven during the free evolution of the other pair. These experiments are performed on an IBM Quantum superconducting processor and demonstrate the significant impact of the staggered DD protocol in suppressing both types of coherent crosstalk. When compared to the standard DD sequences from state-of-the-art methodologies with the application of X2 sequences, our staggered DD protocol enhances circuit fidelity by 19.7% and 8.5%, respectively, in addressing these two crosstalk types.
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