Article
Physics, Multidisciplinary
Mohammadamin Tajik, Ivan Kukuljan, Spyros Sotiriadis, Bernhard Rauer, Thomas Schweigler, Federica Cataldini, Joao Sabino, Frederik Moller, Philipp Schuettelkopf, Si-Cong Ji, Dries Sels, Eugene Demler, Joerg Schmiedmayer
Summary: This experiment verifies the area law of quantum mutual information, which is one of the fundamental properties of equilibrium states of gapped quantum many-body systems. It also investigates the dependence of mutual information on temperature and the separation between subsystems.
Article
Multidisciplinary Sciences
K. J. Satzinger, Y-J Liu, A. Smith, C. Knapp, M. Newman, C. Jones, Z. Chen, C. Quintana, X. Mi, A. Dunsworth, C. Gidney, I Aleiner, F. Arute, K. Arya, J. Atalaya, R. Babbush, J. C. Bardin, R. Barends, J. Basso, A. Bengtsson, A. Bilmes, M. Broughton, B. B. Buckley, D. A. Buell, B. Burkett, N. Bushnell, B. Chiaro, R. Collins, W. Courtney, S. Demura, A. R. Derk, D. Eppens, C. Erickson, L. Faoro, E. Farhi, A. G. Fowler, B. Foxen, M. Giustina, A. Greene, J. A. Gross, M. P. Harrigan, S. D. Harrington, J. Hilton, S. Hong, T. Huang, W. J. Huggins, L. B. Ioffe, S. Isakov, E. Jeffrey, Z. Jiang, D. Kafri, K. Kechedzhi, T. Khattar, S. Kim, P. Klimov, A. N. Korotkov, F. Kostritsa, D. Landhuis, P. Laptev, A. Locharla, E. Lucero, O. Martin, J. R. McClean, M. McEwen, K. C. Miao, M. Mohseni, S. Montazeri, W. Mruczkiewicz, J. Mutus, O. Naaman, M. Neeley, C. Neill, M. Y. Niu, T. E. O'Brien, A. Opremcak, B. Pato, A. Petukhov, N. C. Rubin, D. Sank, V Shvarts, D. Strain, M. Szalay, B. Villalonga, T. C. White, Z. Yao, P. Yeh, J. Yoo, A. Zalcman, H. Neven, S. Boixo, A. Megrant, Y. Chen, J. Kelly, V Smelyanskiy, A. Kitaev, M. Knap, F. Pollmann, P. Roushan
Summary: The discovery of topological order revolutionized the understanding of quantum matter and laid the theoretical groundwork for quantum error-correcting codes. By preparing the ground state of the toric code Hamiltonian on a superconducting quantum processor, researchers were able to measure topological entanglement entropy and simulate anyon interferometry. Investigating aspects of the surface code, including logical state injection and the decay of nonlocal order parameter, showed the potential of quantum processors in studying topological quantum matter and error correction mechanisms.
Article
Physics, Multidisciplinary
Pengfei Zhang, Zhenhua Yu
Summary: In closed generic many-body systems, the process of information scrambling, which disperses local quantum information into highly nonlocal objects, is quantified by the growth of operator size. However, the impact of couplings to the environment on this process remains unexplored. In this study, we predict a dynamical transition in quantum systems with all-to-all interactions accompanied by an environment, separating two phases: a dissipative phase where information scrambling halts and an operator size decays with time, and a scrambling phase where dispersion of information persists, the operator size grows and saturates in the long-time limit. Our prediction is derived from a general argument based on epidemiological models and demonstrated analytically via solvable Brownian Sachdev-Ye-Kitaev models. We also provide evidence that suggests this transition is generic to quantum chaotic systems when coupled to an environment.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Davi Geiger
Summary: Quantum physics sees probability as a subjective belief, and this perspective is applied using Bayesian statistics. The paper presents a Bayesian derivation of the probability density function in phase space and introduces the Kullback-Liebler divergence to define interference and entanglement. The relationships between these quantities and entropy are compared. A brief explanation of entanglement in phase space for the spin degree of freedom and an extension to mixed states are also provided.
Article
Astronomy & Astrophysics
Seyed Ali Hosseini Mansoori, Orlando Luongo, Stefano Mancini, Mirmani Mirjalali, Morteza Rafiee, Alireza Tavanfar
Summary: This study investigates the entanglement entropies, Page times, and scrambling times of eternal planar black holes in holographic axion gravity. The results show that the information theoretical aspects of these black holes are determined by the island rule for the entanglement entropy. They also reveal that the radiation entropy grows linearly in the absence of islands, but saturates at late times with asymptotic values set by the Bekenstein-Hawking entropy when islands are present.
Article
Physics, Multidisciplinary
Thomas Schuster, Norman Y. Yao
Summary: In this study, a universal framework is provided to describe the scrambling of quantum information in open systems. It is predicted that the effect of open-system dynamics is fundamentally controlled by operator size distributions and independent of the microscopic error mechanism. This framework demonstrates that open quantum systems exhibit universal classes of information dynamics that fundamentally differ from their unitary counterparts.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Zi Hong Liu, Weilun Jiang, Bin-Bin Chen, Junchen Rong, Meng Cheng, Kai Sun, Zi Yang Meng, Fakher F. Assaad
Summary: The fermion disorder operator reveals the entanglement information at quantum critical points, and its scaling behavior varies in different systems. Continuous symmetries can emerge in certain cases.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Fluids & Plasmas
Piotr Bialas, Piotr Korcyl, Tomasz Stebel
Summary: We present a direct method for estimating the bipartite mutual information of a classical spin system using Monte Carlo sampling enhanced by autoregressive neural networks. The method allows for the study of arbitrary subsystem geometries and can be generalized to classical field theories. We demonstrate its applicability to the Ising model with four partitionings, including a multiply connected even-odd division. Our results show that the area law holds for temperatures away from the critical temperature, with a universal constant term and different proportionality coefficients for the even-odd partitioning.
Article
Physics, Fluids & Plasmas
Yan-Wei Dai, Xi-Hao Chen, Sam Young Cho, Huan-Qiang Zhou
Summary: We study the mutual information between two lattice blocks in one-dimensional infinite lattice systems using von Neumann entropies. By considering the q-state Potts model and spin-1/2 XY model numerically, we observe singular behaviors in block-block mutual information at critical points for quantum phase transitions. The study reveals a consistent power-law decaying behavior of mutual information between lattice blocks as the separation increases, providing insights into critical exponents and their relation with block-block correlation.
Article
Physics, Condensed Matter
Saikat Mondal, Diptiman Sen, Amit Dutta
Summary: In this study, we investigate the disconnected entanglement entropy (DEE) of a periodically modulated Kitaev chain using Floquet theory. We find that the DEE is integer-quantized, serving as a marker for detecting Floquet Majorana edge modes, which are robust against weak spatial disorder and temporal noise. Interestingly, we also observe that the DEE may detect anomalous edge modes generated by periodic driving of nearest-neighbor hopping, although these modes have no topological significance and are not robust against spatial disorder. We also explore the behavior of the DEE in a kicked Ising chain with an integrability breaking interaction that has been experimentally realized.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Physics, Multidisciplinary
Ryuji Takagi, Naoto Shiraishi
Summary: This research shows that allowing correlation among multiple catalysts can provide unlimited power in quantum coherence manipulation. Any state transformation can be achieved with minimal error by covariant operations with catalysts that may create correlation within them while keeping their marginal states intact. This phenomenon, called resource embezzlement, attributes the embezzlement of resources to the correlation generated among multiple catalysts. The study also extends the analysis to general resource theories and provides conditions for feasible transformations assisted by catalysts that involve correlation.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Isaac H. Kim
Summary: The passage discusses the entropy scaling law of quantum many-body states in physics and the efficient dual description in terms of marginal density matrices on bounded regions. It proves a restricted version of the conjecture for translationally invariant systems in two spatial dimensions and derives a closed-form expression for the maximum-entropy density compatible with those marginals. The assumptions of the construction are exactly satisfied by solvable models of topological order and approximately by finite-temperature Gibbs states of certain quantum spin Hamiltonians.
Article
Optics
Paolo Zanardi, Namit Anand
Summary: In this paper, the formalism of the averaged bipartite OTOC is extended to open quantum systems, where dynamics are described by more general quantum channels. The open bipartite OTOC can be treated analytically and reveals competing entropic contributions from information scrambling and environmental decoherence. Special classes of quantum channels, such as dephasing channels and entanglement-breaking channels, are studied analytically to elucidate the subtle interplay between these effects.
Article
Physics, Multidisciplinary
Benoit Estienne, Blagoje Oblak, Jean-Marie Stephan
Summary: The gapless modes on the edge of 4D quantum Hall droplets exhibit anisotropic behavior, with commensurable trapping frequencies leading to periodic trajectories and incommensurable frequencies producing quasi-periodic, ergodic trajectories with fractal correlation features. This highlights the sharp differences between 4D and 2D Hall droplets and demonstrates the dependence of 4D edge modes on the choice of trap, suggesting observable bifurcations due to droplet deformations.
Article
Physics, Multidisciplinary
Hugo A. Camargo, Lucas Hackl, Michal P. Heller, Alexander Jahn, Bennet Windt
Summary: Using lattice techniques, we provide an elementary proof that the decay of both the entanglement of purification and reflected entropy is enhanced with respect to the mutual information behavior by a logarithm of the distance between the subregions. Additionally, we numerically compute the overall coefficients for these quantities of interest in the Ising spin chain at criticality and the related free fermion conformal field theory.
PHYSICAL REVIEW LETTERS
(2021)
Article
Pediatrics
Ranjith Kumar Manokaran, Harshavardhan Mahalingam, Shubha Shankaranarayanan, Devaram Sowmya, Padmasani Venkat Ramanan
Summary: AESD is a clinicoradiological syndrome in children caused by viral or bacterial infections. This case report presents an infant with dengue infection and AESD, who recovered completely following treatment with human immunoglobulin therapy. The study expands the reported spectrum of neurological manifestations of dengue infection.
JOURNAL OF TROPICAL PEDIATRICS
(2021)
Article
Astronomy & Astrophysics
Joseph P. Johnson, Archana Sangwan, S. Shankaranarayanan
Summary: In this study, we investigate an interacting field theory model for the interaction between dark energy and dark matter. By comparing with cosmological data, we find that this interacting model is consistent with observations and obtain quantitative tools to distinguish between interacting and non-interacting dark energy scenarios.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Multidisciplinary
Manu Srivastava, S. Shankaranarayanan
Summary: This study investigates the effects of quantum fluctuations of scalar field stress-tensors in black-hole space-times using semi-classical analysis. A critical length-scale is obtained at which gravitational interactions become significant.
Review
Astronomy & Astrophysics
S. Shankaranarayanan, Joseph P. Johnson
Summary: This review discusses three aspects of modified gravity (MG) theories: why we need to consider MG theories, how to modify general relativity (GR), and the observational consequences. The review aims to serve as a reference for theorists, observers, and those interested in bridging the gap between theory and observations, by exploring the differences between GR and modified gravity theories.
GENERAL RELATIVITY AND GRAVITATION
(2022)
Article
Astronomy & Astrophysics
Ashu Kushwaha, Abhishek Naskar, Debottam Nandi, S. Shankaranarayanan
Summary: At astrophysical and cosmological scales, there is a detectable amount of magnetic field. This paper proposes an Effective Field Theory (EFT) approach to describe the origin and generation mechanism of magnetic field in the early Universe, based on expansion about the Hubble parameter and its derivatives. By analyzing a specific model, it is confirmed that broken conformal invariance and causal propagation are two necessary conditions for the generation of primordial magnetic fields.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Saurya Das, S. Shankaranarayanan, Vasil Todorinov
Summary: A recent study establishes the correspondence between the Generalized Uncertainty Principle (GUP) and Modified theories of gravity, particularly Stelle gravity. The study investigates the implications of this correspondence for inflation and cosmological observables by evaluating the power spectrum of perturbations using two different methods. By utilizing PLANCK observations, the GUP parameter gamma(0) is determined and its value is used to study the effects of quantum gravity on the power spectrum of primordial gravitational waves and their detectability in future detectors.
Article
Physics, Multidisciplinary
Indranil Das, Joseph P. Johnson, S. Shankaranarayanan
Summary: In this study, two classes of Ricci-inverse models are considered and numerically solved. The results show that these two classes of models cannot explain the late-time evolution of the Universe. By using the reduced action approach, it is found that the no-go theorem for Ricci-inverse gravity models cannot be bypassed. Finally, the implications for early-Universe cosmology are discussed.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Astronomy & Astrophysics
Swastik Bhattacharya, S. Shankaranarayanan
Summary: This work describes the interaction between non-stationary black hole horizons and external fields using effective field theory methods, providing insights beyond classical black hole physics. The authors construct a low-energy effective field theory description for the horizon-fluid of a 4-dimensional, asymptotically flat, Einstein black hole, finding that a deformed Conformal Field Theory can naturally satisfy the requirements of near-horizon symmetries and length scales due to external perturbations. The study also determines the mass and viscosity of the horizon-fluid, which affects the scrambling time of black holes.
Article
Multidisciplinary Sciences
Avijit Chowdhury, Semin Xavier, S. Shankaranarayanan
Summary: Motivations for modified gravity have grown in the last two decades, both at theoretical and observational levels. While f(R) and Chern-Simons gravity have received more attention as simpler generalizations, they lack other modes present in modified theories of gravity. In contrast, quadratic gravity (Stelle gravity) is a more general second-order modification that includes a massive spin-2 mode. Through the study of gravitational wave energy-flux and backreaction on the spacetime of black holes, it has been demonstrated that the massive spin-2 mode carries more energy than the spin-0 mode. These effects are particularly pronounced for intermediate-mass black holes, making them important targets for LISA.
SCIENTIFIC REPORTS
(2023)
Article
Astronomy & Astrophysics
Sandra Byju, Kinjalk Lochan, S. Shankaranarayanan
Summary: We investigate generalized thermalization in an isolated free fermionic chain that undergoes a sudden quench from an out of equilibrium initial state. We focus on the evolution of local observables after the quench, such as occupation number, hopping between nearest neighbors, information sharing, and out-of-time-order correlations. We find that the system relaxes to a generalized Gibbs ensemble, despite the belief that noninteracting or free fermionic models do not relax to such an ensemble. Our analysis reveals that the internal interactions within the system become less important once the quench is sufficiently strong.
Article
Astronomy & Astrophysics
S. Mahesh Chandran, S. Shankaranarayanan
Summary: In time-independent quantum systems, the entanglement entropy possesses a scaling symmetry that the energy of the system does not have. We extend this symmetry to time-dependent systems including coupled harmonic oscillators and quantum scalar fields. These time-dependent systems exhibit a dynamical scaling symmetry that preserves the evolution of various measures of quantum correlations. It is shown that instabilities in these systems can be quantified using scrambling time and Lyapunov exponents, and that the delayed decay of the Loschmidt echo is determined by inverted modes. We also discuss the implications of zero modes and inverted modes in time-dependent massive scalar fields in different spacetimes, such as cosmological and black hole spacetimes.
Article
Education, Scientific Disciplines
Karthik Rajeev, S. Shankaranarayanan
Summary: Formulating a satisfactory quantum theory of gravity is a challenging task in theoretical physics, and Thanu Padmanabhan's pioneering works in black hole physics, quantum cosmology, and quantum gravity are considered insightful and unique. This article briefly reviews his contributions in these fields.
RESONANCE-JOURNAL OF SCIENCE EDUCATION
(2023)
Article
Astronomy & Astrophysics
Susmita Jana, S. Shankaranarayanan
Summary: The gravitational memory effect and its electromagnetic analog are potential probes in the strong gravity regime. Researchers evaluated the electromagnetic (EM) memory effect for comoving observers in arbitrary curved spacetimes, providing a transparent and easily applicable expression for the EM memory in general curved spacetimes. The master equation derived in this study allows for a physical understanding of the contribution to the EM memory and demonstrates the advantages of this approach in obtaining EM memory for specific spacetime geometries.
Article
Statistics & Probability
S. Farzana, Gayathri Harikumar, S. Shankaranarayanan, N. Vikram
Summary: Banks are no longer solely focused on satisfying consumers, but are now paying attention to providing a delightful banking experience. Research shows that e-services have an impact on customer satisfaction in the banking industry, with responsiveness and reliability being the most important factors.
JOURNAL OF STATISTICS AND MANAGEMENT SYSTEMS
(2022)
Article
Astronomy & Astrophysics
Semin Xavier, Alan Sunny, S. Shankaranarayanan
Summary: In this study, an exact time-dependent solution modeling evaporating black holes in the cosmological background was obtained, considering mass-loss, mass distribution, and cosmological background as the three aspects of primordial black holes (PBHs). The research also found that the decay rate of PBHs is positively correlated with their mass. This is significant for understanding the theoretical constraints on PBHs as dark matter.