The European Physical Journal H最新文献_第8页

The breakthrough of a quantum chemist by classical dynamics: Martin Karplus and the birth of computer simulations of chemical reactions 经典动力学中量子化学家的突破:马丁·卡普拉斯和计算机模拟化学反应的诞生

IF 1 4区物理与天体物理

The European Physical Journal H Pub Date : 2021-06-10 DOI: 10.1140/epjh/s13129-021-00013-w

Daniele Macuglia, Benoît Roux, Giovanni Ciccotti

引用次数: 1

The early years of quantum Monte Carlo (1): the ground state 早期的量子蒙特卡罗(1):基态

IF 1 4区物理与天体物理

The European Physical Journal H Pub Date : 2021-06-08 DOI: 10.1140/epjh/s13129-021-00017-6

Michel Mareschal

引用次数: 3

Arguments against the flatness problem in classical cosmology: a review 经典宇宙学中反对平坦性问题的争论:综述

IF 1 4区物理与天体物理

The European Physical Journal H Pub Date : 2021-04-26 DOI: 10.1140/epjh/s13129-021-00006-9

Phillip Helbig

{"title":"Arguments against the flatness problem in classical cosmology: a review","authors":"Phillip Helbig","doi":"10.1140/epjh/s13129-021-00006-9","DOIUrl":"https://doi.org/10.1140/epjh/s13129-021-00006-9","url":null,"abstract":"Several authors (including myself) have made claims, none of which has been convincingly rebutted, that the flatness problem, as formulated by Dicke and Peebles, is not really a problem but rather a misunderstanding. In particular, we all agree that no fine-tuning in the early Universe is needed in order to explain the fact that there is no strong departure from flatness, neither in the early Universe nor now. Nevertheless, the flatness problem is still widely perceived to be real, since it is still routinely mentioned as an outstanding (in both senses) problem in cosmology in papers and books. Most of the arguments against the idea of a flatness problem are based on the change with time of the density parameter (varOmega ) and normalized cosmological constant (lambda ) (often assumed to be zero before there was strong evidence that it has a non-negligible positive value) and, since the Hubble constant H is not considered, are independent of time scale. In addition, taking the time scale into account, it is sometimes claimed that fine-tuning is required in order to produce a Universe which neither collapsed after a short time nor expanded so quickly that no structure formation could take place. None of those claims is correct, whether or not the cosmological constant is assumed to be zero. I briefly review the literature disputing the existence of the flatness problem, which is not as well known as it should be, compare it with some similar persistent misunderstandings, and wonder about the source of confusion.","PeriodicalId":791,"journal":{"name":"The European Physical Journal H","volume":"46 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4993445","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}

引用次数: 0

The Moore–Penrose inverse: a hundred years on a frontline of physics research 摩尔-彭罗斯逆:物理学研究前沿的一百年

IF 1 4区物理与天体物理

The European Physical Journal H Pub Date : 2021-04-21 DOI: 10.1140/epjh/s13129-021-00011-y

Oskar Maria Baksalary, Götz Trenkler

引用次数: 19

Was physics ever deterministic? The historical basis of determinism and the image of classical physics 物理学曾经是决定性的吗?决定论的历史基础与经典物理学的形象

IF 1 4区物理与天体物理

The European Physical Journal H Pub Date : 2021-04-01 DOI: 10.1140/epjh/s13129-021-00012-x

Marij van Strien

引用次数: 4

60 Years of neutral particle analysis: from early tokamaks to ITER 中性粒子分析60年:从早期的托卡马克到ITER

IF 1 4区物理与天体物理

The European Physical Journal H Pub Date : 2021-03-19 DOI: 10.1140/epjh/s13129-021-00009-6

M. P. Petrov, V. I. Afanasyev, F. V. Chernyshev, P. R. Goncharov, M. I. Mironov, S. Ya. Petrov

{"title":"60 Years of neutral particle analysis: from early tokamaks to ITER","authors":"M. P. Petrov, V. I. Afanasyev, F. V. Chernyshev, P. R. Goncharov, M. I. Mironov, S. Ya. Petrov","doi":"10.1140/epjh/s13129-021-00009-6","DOIUrl":"https://doi.org/10.1140/epjh/s13129-021-00009-6","url":null,"abstract":"Academician A.?D.?Sakharov’s idea concerning the emission of atomic flux from hot plasma (1951) inspired scientists of A.?F.?Ioffe Physico-Technical Institute to create the first in the world instrument called Neutral Atom Analyzer in 1960 and then in 1961 to use it successfully on the Alpha device (USSR, 1958–1963). Now the analysis of fluxes of fast atoms referred to as Neutral Particle Analysis (NPA) is one of the main diagnostic methods for the ion component of plasma in tokamaks, stellarators, and other devices. NPA provides a unique opportunity for studying the ion distribution functions, ion temperatures and hydrogen isotope ratio in hot plasma. Neutral particle analyzers developed at the Ioffe Institute were widely used in the USSR until the late 1970s, and afterwards began to be employed worldwide. Since then, most of the information on the ion distribution functions and the behavior of fast ions in fusion plasma is obtained from NPA measurements on all leading magnetic confinement fusion systems worldwide. The specialized complex of atom analyzers currently being created at the Ioffe Institute is included in the primary list of ITER diagnostics. The integration of this complex on ITER is expected to begin in 2025.","PeriodicalId":791,"journal":{"name":"The European Physical Journal H","volume":"46 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4759004","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}

引用次数: 4

The history of LHCb LHCb的历史

IF 1 4区物理与天体物理

The European Physical Journal H Pub Date : 2021-03-19 DOI: 10.1140/epjh/s13129-021-00002-z

I. Belyaev, G. Carboni, N. Harnew, C. Matteuzzi, F. Teubert

{"title":"The history of LHCb","authors":"I. Belyaev, G. Carboni, N. Harnew, C. Matteuzzi, F. Teubert","doi":"10.1140/epjh/s13129-021-00002-z","DOIUrl":"https://doi.org/10.1140/epjh/s13129-021-00002-z","url":null,"abstract":"In this paper, we describe the history of the LHCb experiment over the last three decades, and its remarkable successes and achievements. LHCb was conceived primarily as a ({b} )-physics experiment, dedicated to (CP) violation studies and measurements of very rare ({{b}} ) decays; however, the tremendous potential for ({c} )-physics was also clear. At first data taking, the versatility of the experiment as a general-purpose detector in the forward region also became evident, with measurements achievable such as electroweak physics, jets and new particle searches in open states. These were facilitated by the excellent capability of the detector to identify muons and to reconstruct decay vertices close to the primary ({{p}} {{p}} )?interaction region. By the end of the LHC Run 2 in 2018, before the accelerator paused for its second long shut down, LHCb had measured the CKM quark mixing matrix elements and (CP) violation parameters to world-leading precision in the heavy-quark systems. The experiment had also measured many rare decays of ({b} ) ?and ({c} ) ?quark mesons and baryons to below their Standard Model expectations, some down to branching ratios of order 10(^{-9}). In addition, world knowledge of ({{b}} ) and ({{c}} ) spectroscopy had improved significantly through discoveries of many new resonances already anticipated in the quark model, and also adding new exotic four and five quark states. The paper describes the evolution of the LHCb detector, from conception to its operation at the present time. The authors’ subjective summary of the experiment’s important contributions is then presented, demonstrating the wide domain of successful physics measurements that have been achieved over the years.","PeriodicalId":791,"journal":{"name":"The European Physical Journal H","volume":"46 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5057338","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}

引用次数: 8

Historical and philosophical reflections on the Einstein-de Sitter model 对爱因斯坦-德西特模型的历史和哲学思考

IF 1 4区物理与天体物理

The European Physical Journal H Pub Date : 2021-03-19 DOI: 10.1140/epjh/s13129-021-00007-8

Cormac O’Raifeartaigh, Michael O’Keeffe, Simon Mitton

{"title":"Historical and philosophical reflections on the Einstein-de Sitter model","authors":"Cormac O’Raifeartaigh, Michael O’Keeffe, Simon Mitton","doi":"10.1140/epjh/s13129-021-00007-8","DOIUrl":"https://doi.org/10.1140/epjh/s13129-021-00007-8","url":null,"abstract":"We present some historical and philosophical reflections on the paper “On the Relation Between the Expansion and the Mean Density of the Universe”, published by Albert Einstein and Willem de Sitter in 1932. In this famous work, Einstein and de Sitter considered a relativistic model of the expanding universe with both the cosmological constant and the curvature of space set to zero. Although the Einstein-deSitter model went on to serve as a standard model in ‘big bang’ cosmology for many years, we note that the authors do not explicitly consider the evolution of the cosmos in the paper. Indeed, the mathematics of the article are quite puzzling to modern eyes. We consider claims that the paper was neither original nor important; we find that, by providing the first specific analysis of the case of a dynamic cosmology without a cosmological constant or spatial curvature, the authors delivered a unique, simple model with a straightforward relation between cosmic expansion and the mean density of matter that set an important benchmark for both theorists and observers. We consider some philosophical aspects of the model and provide a brief review of its use as a standard ‘big bang’ model over much of the (20{mathrm {th}}) century.","PeriodicalId":791,"journal":{"name":"The European Physical Journal H","volume":"46 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5057387","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}

引用次数: 1

Exploring the boundary between atoms and the continuum by computers: a personal history 用计算机探索原子和连续体之间的边界:个人历史

IF 1 4区物理与天体物理

The European Physical Journal H Pub Date : 2021-03-18 DOI: 10.1140/epjh/s13129-021-00010-z

Brad Lee Holian

引用次数: 0

N.R. Sen: Father of Indian Applied mathematics N.R.森:印度应用数学之父

IF 1 4区物理与天体物理

The European Physical Journal H Pub Date : 2021-03-04 DOI: 10.1140/epjh/s13129-021-00003-y

Saibal Ray, Utpal Mukhopadhyay, Rajinder Singh

引用次数: 0