检索结果-南通市图书馆

Quantum algorithms for matrix operations and linear systems of equations

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第3期76卷 100-112页

作者： Wentao Qi Alexandr I Zenchuk Asutosh Kumar Junde Wu School of Mathematical Sciences Zhejiang UniversityHangzhou 310027China Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry RAS ChernogolovkaRussia P.G.Department of Physics Gaya CollegeMagadh UniversityRampurGaya 823001India harish-Chandra Research Institute HBNIChhatnag RoadJhunsiPrayagraj 211019India Vaidic and Modern Physics Research Centre Bhagal BhimBhinmalJalore 343029India

Fundamental matrix operations and solving linear systems of equations are ubiquitous in scientific *** the‘sender-receiver’model,we propose quantum algorithms for matrix operations such as matrix-vector product,matrix-matrix product,the sum of two matrices,and the calculation of determinant and inverse *** encode the matrix entries into the probability amplitudes of the pure initial states of *** applying proper unitary transformation to the complete quantum system,the desired result can be found in certain blocks of the receiver’s density *** quantum protocols can be used as subroutines in other quantum ***,we present an alternative quantum algorithm for solving linear systems of equations.

关键词： matrix operation systems of linear equations ‘sender-receiver’quantum computation model quantum algorithm

A modified TreePM code

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2009年第8期9卷 861-873页

作者： Nishikanta Khandai J. S. Bagla harish-Chandra Research Institute

We discuss the performance characteristics of using the modification of the tree code suggested by Barnes in the context of the TreePM code. The optimization involves identifying groups of particles and using only one tree walk to compute the force for all the particles in the group. This modification has been in use in our implementation of the TreePM code for some time, and has also been used by others in codes that make use of tree structures. We present the first detailed study of the performance characteristics of this optimization. We show that the modification, if tuned properly, can speed up the TreePM code by a significant amount. We also combine this modification with the use of individual time steps and indicate how to combine these two schemes in an optimal fashion. We find that the combination is at least a factor of two faster than the modified TreePM without individual time steps. Overall performance is often faster by a larger factor because the scheme for the groups optimizes the use of cache for large simulations.

关键词： cosmology large-scale structure of universe -- gravitation -- methods numerical

Magnetic Field of a Compact Spherical Star under f(R,T) Gravity

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2018年第9期35卷 104-108页

作者： Safiqul Islam Shantanu Basu harish-Chandra Research Institute HBNI Department of Physics and Astronomy The University of Western Ontario

We present the interior solutions of distributions of magnetized fluid inside a sphere in f（R, T） gravity. Tile magnetized sphere is embedded in an exterior Reissner NordstrOm metric. We assume that all physical quantities are in static equilibrium. The perfect fluid matter is studied under a particular form of the Lagrangian density f（R, T）. The magnetic field profile in modified gravity is calculated. Observational data of neutron stars are used to plot suitable models of magnetized compact objects. We reveal the effect of f（R, T） gravity on the magnetic field profile, with application to neutron stars, especially highly magnetized neutron stars found in x-ray pulsar systems. Finally, the effective potential Veff and innermost stable circular orbits, arising out of the motion of a test particle of negligible mass influenced by attraction or repulsion from the massive center, are discussed.

关键词： Gravity Magnetic Field of a Compact Spherical Star under f R,T

Hadronic light-by-light scattering contribution to the muon g-2

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2010年第6期34卷 705-711页

作者： A.Nyffeler Regional Centre for Accelerator-based Particle Physics Harish-Chandra Research Institute

We review recent developments concerning the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon. We first discuss why fully off-shell hadronic form factors should be used for the evaluation of this contribution to the g- 2. We then reevaluate the numerically dominant pion-exchange contribution in the framework of large-No QCD, using an off-shell pion-photon-photon form factor which fulfills all QCD short-distance constraints, in particular, a new short-distance constraint on the off-shell form factor at the external vertex in g- 2, which relates the form factor to the quark condensate magnetic susceptibility in QCD. Combined with available evaluations of the other contributions to hadronic light-by-light scattering this leads to the new result αμ^LbyL;had= （116±40） × 10^-11, with a conservative error estimate in view of the many still unsolved problems. Some potential ways for further improvements are briefly discussed as well. For the electron we obtain the new estimate αe^LbyL;had= （3.9± 1.3） × 10^-14.

关键词： muon anomalous magnetic moment hadronic contributions effective field theories large-No

Pairs of integers which are mutually squares

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2017年第9期60卷 1633-1646页

作者： CHAKRABORTY Kalyan JIMENEZ URROZ Jorge PAPPALARDI Francesco Department of Mathematics Harish Chandra Research InstituteAllahabad 211019India Department of Mathemdticas Universidad Politecnica de CatalunyaBarcelona 08034Spain Dipartimento di Matematica Universith Roma TreRoma 1-00146Italy

We derived an asymptotic formula for the number of pairs of integers which are mutually squares. Earlier results dealt with pairs of integers subject to the restriction that they are both odd, co-prime and squarefree. Here we remove all these restrictions and prove （similar to the best known one with restrictions） cx2/log X with an absolute constant c that the number of such pair of integers upto a large real X is asymptotic to which we give explicitly. Our error term is also compatible to the best known one.

关键词： quadratic reciprocity mutually squares Jacobi symbol

Quantum Path Predictability for an Electronic Mach-Zehnder Interferometer in Presence of Environment Induced Decoherence and Quantum Erasing Process

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Physics 2016年第9期7卷 892-898页

作者： Samyadeb Bhattacharya Sisir Roy harish-Chandra Research Institute Allahabad India National Institute of Advanced Studies IISC Campus Bangalore India

In this paper, we have estimated the temperature dependent path predictability for an electronic Mach-Zehnder interferometer. The increment of path predictability can directly be associated with stronger decoherence process. We have also theoretically predicted that placing two detectors in both the paths, which are at the same equilibrium temperature with the system, erases all the memory of path information and hence acts like a quantum eraser.

关键词： Path Predictability Quantum Interference Decoherence Open Quantum Systems

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国是我的第二故乡

神州学人 2015年第1期 22-23页

作者：哈利仕 harish Chandro Shah

我是尼泊尔人，职业是医生，现任尼泊尔首都国家医院院长、尼中文化教育协会主席。我父亲曾经去过中国，他告诉我，中国是我们的友好邻邦。中国人民非常友好，很善良。中国是尼泊尔始终如一的朋友，中国在自己困难的时候也在帮助尼泊尔... 详细信息

我是尼泊尔人，职业是医生，现任尼泊尔首都国家医院院长、尼中文化教育协会主席。我父亲曾经去过中国，他告诉我，中国是我们的友好邻邦。中国人民非常友好，很善良。中国是尼泊尔始终如一的朋友，中国在自己困难的时候也在帮助尼泊尔。这些话深深地影响着我，使我打心底里对中国充满了期望。

关键词：第二故乡国是中国人民尼泊尔教育协会中文化

Music as Mathematics of Senses

在线全文

学校读者我要写书评

暂无评论

Advances in Pure Mathematics 2018年第12期8卷 845-862页

作者： Hailong Li Kalyan Chakraborty Shigeru Kanemitsu Department of Mathematics Weinan Normal University Weinan China harish-Chandra Research Institute Allahabad India Faculty of Engineering Kyushu Institute of Technology Kitakyushu Japan

It is often said that music has reached its supreme and highest level in the 18th and 19th centuries. One of the main reasons for this achievement seems to be the robust structure of compositions of music, somewhat remindful of robust structure of mathematics. One is reminded of the words of Goethe: Geometry is frozen music. Here, we may extend geometry to mathematics. For the Middle Age in Europe, there were seven main subjects in the universities or in higher education. They were grammar, logic and rhetoric—these three (tri) were regarded as more standard and called trivia (trivium), the origin of the word trivial. And the remaining four were arithmetic, geometry, astronomy and music—these four (quadrus) were regarded as more advanced subjects and were called quadrivia (quadrivium). Thus for Goethe, geometry and mathematics seem to be equivocal. G. Leibniz expresses more in detail in his letter to C. Goldbach in 1712 (April 17): Musica est exercitium arithmeticae occultum nescientis se numerari animi (Music is a hidden arithmetic exercise of the soul, which doesn’t know that it is counting). Or in other respects, J. Sylvester expresses more in detail: Music is mathematics of senses. Mathematics is music of reasons. Thus, the title arises. This paper is a sequel to [1] and examines mathematical structure of musical scales entailing their harmony on expanding and elaborating material in [2] [3] [4] [5], etc. In statistics, the strong law of large numbers is well-known which claims that This means that the relative frequency of occurrences of an event A tends to the true probability p of the occurrences of A with probability 1. In music, harmony is achieved according to Pythagoras’ law of small numbers, which claims that only the small integer multiples of the fundamental notes can create harmony and consonance. We shall also mention the law of cyclotomic numbers according to Coxeter, which elaborates Pythagoras’ law and suggests a connection with construction of n-g

关键词： Pythagorean Scale Just Intonation Temperament Beat Pythagoras’ Law of Small Numbers Law of Cyclotomic Numbers

Wave and particle properties can be spatially separated in a quantum entity

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Photonics Research 2021年第7期9卷 1379-1383页

作者： PRATYUSHA CHOWDHURY ARUN KUMAR PATI JING-LING CHEN Indian Institute of Technology Guwahati GuwahatiAssam 781039India Quantum Information and Computation Group Harish-Chandra Research InstituteJhunsiAllahabad 211019India Theoretical Physics Division Chern Institute of MathematicsNankai UniversityTianjin 300071China

Wave and particle are two fundamental properties of nature. The wave–particle duality has indicated that a quantum object may exhibit the behaviors of both wave and particle,depending upon the circumstances of the experiment. The major significance of wave–particle duality has led to a fundamental equation in quantum mechanics:the Schr?dinger equation. At present,the principle of wave–particle duality has been deeply rooted in people’s hearts. This leads to a common-sense perception that wave property and particle property coexist simultaneously in a quantum entity,and these two physical attributes cannot be completely separated from each other. In classical physics,a similar common-sense thought is that a physical system is inseparable from its physical ***,this has been recently challenged and beaten by a quantum phenomenon called the "quantum Cheshire cat," in which a cat and its grin can be spatially separated. In this work,we propose a thought experiment based on the technology similar to the quantum Cheshire cat. We find that wave and particle attributes of a quantum entity can be completely separated,thus successfully dismantling the wave–particle duality for a quantum entity. Our result is still consistent with the complementarity principle and deepens the understanding of quantum foundations.

关键词： properties. equation. quantum