Identifying quantum many-body integrability and chaos using eigenstates trace distances

While the concepts of quantum many-body integrability and chaos are of fundamental importance for the understanding of quantum matter, their precise definition has so far remained an open question. In this work, we introduce an alternative indicator for quantum many-body integrability and chaos, which is based on the statistics of eigenstates by means of nearest-neighbor subsystem trace distances. We show that this provides us with a faithful classification through extensive numerical simulations for a large variety of paradigmatic model systems including random matrix theories, free fermions, Bethe-ansatz solvable systems, and models of many-body localization. While existing indicators, such as those obtained from level-spacing statistics, have already been utilized with great success, they also face limitations. This concerns for instance the quantum many-body kicked top, which is exactly solvable but classified as chaotic in certain regimes based on the level-spacing statistics, while our introduced indicator signals the expected quantum many-body integrability. We discuss the universal behaviors we observe for the nearest-neighbor trace distances and point out that our indicator might be useful also in other contexts such as for the many-body localization transition.Comment: 7+6 pages, 3+6 Figure

Universal logarithmic correction to Rényi (Shannon) entropy in generic systems of critical quadratic fermions

The R\'enyi (Shannon) entropy, i.e. $Re_{\alpha}(Sh)$, of the ground state of quantum systems in local bases normally show a volume-law behavior. For a subsystem of quantum chains at critical point there is an extra logarithmic subleading term with a coefficient which is universal. In this paper we study this coefficient for generic time-reversal translational invariant quadratic critical free fermions. These models can be parameterized by a complex function which has zeros on the unit circle. When the zeros on the unit circle do not have degeneracy and there is no zero outside of the unit circle we are able to classify the coefficient of the logarithm. In particular, we numerically calculate the R\'enyi (Shannon) entropy in configuration basis for wide variety of these models and show that there are two distinct classes. For systems with $U(1)$ symmetry the coefficient is proportional to the central charge, i.e. one half of the number of points that one can linearize the dispersion relation of the system; for all the values of $\alpha$ with transition point at $\alpha=4$. For systems without this symmetry, when $\alpha>1$ this coefficient is again proportional to the central charge. However, the coefficient for $\alpha\leq 1$ is a new universal number. Finally, by using the discrete version of Bisognano-Wichmann modular Hamiltonian of the Ising chain we show that these coefficients are universal and dependent on the underlying CFT.Comment: v2: 16 pages, 10 figures published versio

Scientometric Analysis of the Scientometric Literature

 Using bibliographic records from the Social Science Citation Index, Science Citation Index, and Arts & Humanities Citation Index, this paper tries to give a complete view of the evolution of the field of Scientometrics based on its literature published during 1980 to 2009. This is a descriptive survey using scientometric indicators.Findings revealed that out of 691 articles in the field of Scientometrics, a total number of 183 articles (26.48%) were written during 1980 to 2009 by the top ten authors. Some of these articles were produced in authors’ collaboration and some of them were by single authors.   Geographical analysis indicated that the field had evolved considerably in different regions of the world. Hungarian Academy of Science with 40 records (5.71%) was the most productive institution in the field of Scientometrics. Furthermore, chronological analysis disclosed that the scientific production in the field of Scientometrics showed a slow increase from 1980 to 2009. The overwhelming majority of documents were in English, and the international journal of Scientometrics was the most prolific journal in the field. It has also been declared that 67.87% of the literature was published in the area of Library and Information Science

Scientific Productions and Authorship Patterns of Top Ten Iranian Scientists

Using bibliographic records from the Social Science Citation Index, Science Citation Index, and Arts & Humanities Index, this paper tries to give a complete view of the characteristics of top ten Iranian authors during 1990-2007 according to their authorship pattern. Findings revealed that during 1990-2007 a total of 2650 articles were written by top ten Iranian authors. Findings showed that M. Shamsipour with 463 articles is the most productive scientist of Iran during the studied period. M. M. Heravi with 365 articles and M. Ganjali with 283 articles appeared in the table at second and third positions, respectively. Findings revealed that overwhelmingly the majority of articles (97/69%) written by Iranian top authors are the result of collaborative works and the authors are highly inclined towards collaborative rather than non-collaborative research. There was a remarkable relationship between co-authorship and number of citations. More-than-three-author articles received the most number of citations. On the other hand, it seems that international collaboration of Iranian top authors is not significant

Many-Body Synchronization in a Classical Hamiltonian System

We study synchronization between periodically driven, interacting classical spins undergoing a Hamiltonian dynamics. In the thermodynamic limit there is a transition between a regime where all the spins oscillate synchronously for an infinite time with a period twice the driving period (synchronized regime) and a regime where the oscillations die after a finite transient (chaotic regime). We emphasize the peculiarity of our result, having been synchronization observed so far only in driven-dissipative systems. We discuss how our findings can be interpreted as a period-doubling time crystal and we show that synchronization can appear both for an overall regular and overall chaotic dynamics

How to increase the loyalty of public library users? A qualitative study

The main objective of this study is to explain how to increase user loyalty behavior to public library services. This study uses a qualitative method based on grounded theory. The research population included users of public libraries in Iran. The data were collected through in-depth interviews, and the theoretical saturation was obtained after interviewing 24 members of public libraries. The collected data through interviews were analyzed using theoretical coding and content analysis. Results indicated that observing moral and humane principles when dealing with library users plays a significant role in both building user loyalty to the library and attracting new users. In addition, it was found that causal conditions in increasing loyalty among public library users are related to four areas including physical space management, information resource management, human resource management, and information technology management. It was also noted that factors such as service quality, proper design of interiors, providing diverse and updated information resources, the use of new communication technologies, and the use of cyberspace and social network applications must be taken into account by public libraries. Building loyalty among users and members of public libraries in today�s technological world is of high importance, as it will guarantee the repeated and more frequent use of public libraries and their services and thus reflect their positive effects. The loyalty of users of libraries and information centers can be based on perceived quality, effective communication between librarians and users, and satisfaction with services offered by libraries and their staffs and can affect the intention for repeated visits, and the use of library service and preferring a library over other libraries. © The Author(s) 2019

A story of transformation of an iranian rural library in nonformal education of children and the life of people

This research shows how a rural library (named Fatemeha Library) in Iran can be transformed into a successful one and how it is possible to introduce a prototype for the establishment and development of rural libraries in less developed regions of the world. The study was a qualitative one based on both narrative research and grounded theory. The research population consisted of 13 key informants. After the implementation of interviews and field notes, data were analyzed using open coding, axial coding, and selective coding. Based on the paradigmatic model of research, it was found that Fatemeha Library, as a phenomenological basis, has played a central role in the process of transformation in the nonformal education of children and the reading culture of the villagers. The results showed that the basic factor in this qualitative paradigm leads to rural development with the centrality of a rural library. © 2020 by The University of Chicago. All rights reserved

Patterns of Iran's research collaboration in the field of pharmacology and pharmacy: A bibliometric study

Purpose: This research aims to analyze and visualize the structure of Iranian scholarly networks in the field of “pharmacology and pharmacy”. This study includes an overview of co-authorship, efficiency and ranking of the researches, visualizing the co-authorship network, changes in the main core of the publications and macro and micro-level metrics such as social influence. Methods: This research utilizes social network analysis (SNA). The preliminary data of this research includes all the Iran’s documents in Web of Science in “Pharmacology and Pharmacy” during the period of 2005 to 2016. After the preprocessing of 6204 records and creating relational matrix, a combination of bibliometric software (including UCINET, NetDraw, HistCite and VOSviewer) were used to analyze and uncover network features. Results: Results indicated that most papers are multi-authored. Four-authored articles are the main common authorship pattern. Some measures such as author frequency, multi-authored papers, and single-authored papers in each time interval are ascending. Moreover, “density” reduction of the scientific collaborations indicates that fragmentation level has increased based on the “clustering coefficient” in each period. Besides, Iranian researchers of the field has the most collaboration with the scholars of England (%2.85), U.S.A. (2.61%) and Canada (1.76%), respectively. Conclusions: Fragile structure and low closeness of the network imply low maturity of Iran’s research in the field of “pharmacology and pharmacy”. Also, test of the correlation coefficients indicates that with increasing “degree centrality” and “betweenness centrality”, the “number of articles” increases as well. However, there is no correlation between “closeness centrality” and “number of articles”

Discrete truncated Wigner approach to dynamical phase transitions in Ising models after a quantum quench

By means of the discrete truncated Wigner approximation, we study dynamical phase transitions arising in the steady state of transverse-field Ising models after a quantum quench. Starting from a fully polarized ferromagnetic initial condition, these transitions separate a phase with nonvanishing magnetization along the ordering direction from a disordered symmetric phase upon increasing the transverse field. We consider two paradigmatic cases, a one-dimensional long-range model with power-law interactions proportional to 1/r(alpha) decaying algebraically as a function of distance r and a two-dimensional system with short-range nearest-neighbor interactions. In the former case, we identify dynamical phase transitions for alpha less than or similar to 2 and we extract the critical exponents from a data collapse of the steady-state magnetization for up to 1200 lattice sites. We find identical exponents for alpha less than or similar to 0.5, suggesting that the dynamical transitions in this regime fall into the same universality class as the nonergodic mean-field limit. The two-dimensional Ising model is believed to be thermalizing, which we also confirm using exact diagonalization for small system sizes. Thus, the dynamical transition is expected to correspond to the thermal phase transition, which is consistent with our data upon comparing to equilibrium quantum Monte Carlo simulations. We further test the accuracy of the discrete truncated Wigner approximation by comparing against numerically exact methods such as exact diagonalization, tensor network, as well as artificial neural network states and we find good quantitative agreement on the accessible time scales. Finally, our work provides an additional contribution to the understanding of the range and the limitations of qualitative and quantitative applicability of the discrete truncated Wigner approximation