发布求助
文献互助 智能选刊 最新文献

Australian Journal of Physics最新文献

筛选
英文 中文
Bulk viscosity and particle creation in Brans—Dicke theory Brans-Dicke理论中的体粘度和颗粒生成
Australian Journal of Physics Pub Date : 1999-11-01 DOI: 10.1071/PH98107
G. Singh, A. Beesham
{"title":"Bulk viscosity and particle creation in Brans—Dicke theory","authors":"G. Singh, A. Beesham","doi":"10.1071/PH98107","DOIUrl":"https://doi.org/10.1071/PH98107","url":null,"abstract":"The efiect of bulk viscosity on the evolution of the spatially ∞at Friedmann{Lemaitre{ Robertson{Walker (FLRW) models in the context of open thermodynamical systems, which allow for particle creation, is analysed within the framework of Brans{Dicke (BD) theory. The BD fleld equations are modifled with the incorporation of a creation pressure and bulk viscous stress. A class of physically plausible models has been taken into consideration. The behaviour of the particle number density and bulk viscosity is discussed with the evolution of the Brans{Dicke scalar fleld.","PeriodicalId":170873,"journal":{"name":"Australian Journal of Physics","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116805716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 30
A new energy-dependent D width in coherent pion production 相干介子产生中一种新的能量依赖的D宽度
Australian Journal of Physics Pub Date : 1999-11-01 DOI: 10.1071/PH99031
P. Deutchman
{"title":"A new energy-dependent D width in coherent pion production","authors":"P. Deutchman","doi":"10.1071/PH99031","DOIUrl":"https://doi.org/10.1071/PH99031","url":null,"abstract":"A new derivation for the energy-dependent Δ width inside nuclei is presented which includes the all important, energy-dependent nuclear form factor describing the decay of the Δ particle from its harmonic oscillator, bound state back to a captured nucleon and outgoing pion. Additional improvements include relativistic kinematics, generalisation beyond the static limit in the kinematics, and inclusion of the ΔN Π energy-dependent vertex form factor. The new decay width provides a reasonable cut-off at high pion momenta and gives the correct momentum dependence in the limit of single-particle decay at low momenta. The results of calculations for the energy-dependent widths and their effects on the energy distributions of exclusive coherent pion production for 12 C+ 12 C → 12 C+ 12 C* (T = 1)+ Π 0 at incident energies below and above the pion threshold are shown and discussed. The new energy dependence is compared to the free Δ width used previously and it is seen that the new results give a smoother and more realistic shape to the pion energy distributions.","PeriodicalId":170873,"journal":{"name":"Australian Journal of Physics","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126182664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Interlayer exchange coupling: doping, interface states and domain wall resonance 层间交换耦合:掺杂、界面态和畴壁共振
Australian Journal of Physics Pub Date : 1999-10-01 DOI: 10.1071/PH99016
R. Stamps
{"title":"Interlayer exchange coupling: doping, interface states and domain wall resonance","authors":"R. Stamps","doi":"10.1071/PH99016","DOIUrl":"https://doi.org/10.1071/PH99016","url":null,"abstract":"Possible interface effects are examined theoretically for oscillatory exchange coupling between ferromagnetic metal films separated by a nonmagnetic spacer film. It is argued that the exchange coupling is sensitive to aspects of the magnetic film’s electronic structure, and evidence from magnetic film doping experiments is described. Possible effects of interface electronic states are also explored. Finally, a suggestion for a new type of domain wall resonance experiment is made that could provide unique measures of local values of the exchange coupling strength.","PeriodicalId":170873,"journal":{"name":"Australian Journal of Physics","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116942891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Calculation of the exchange constant in 2D Wigner liquid 二维维格纳液体交换常数的计算
Australian Journal of Physics Pub Date : 1999-10-01 DOI: 10.1071/PH98103
V. Flambaum, I. Ponomarev, O. Sushkov
{"title":"Calculation of the exchange constant in 2D Wigner liquid","authors":"V. Flambaum, I. Ponomarev, O. Sushkov","doi":"10.1071/PH98103","DOIUrl":"https://doi.org/10.1071/PH98103","url":null,"abstract":"The recent observation of a two-dimensional (2D) metal–insulator transition in semiconductor devices and the strong influence of a magnetic field on the metallic phase has attracted a great deal of interest. This gives rise to the important theoretical question about the nature and the magnetic order of insulating and conducting phases. In the present paper we calculate (both analytically and numerically) the exchange constant for a two-dimensional Wigner liquid— the state with destroyed long-range order but preserved short-range order. It is demonstrated that there is an antiferromagnetic spin–spin interaction between nearest electrons. We also discuss a possible pairing of the electrons in a 2D Wigner crystal by the spin-Peierls mechanism.","PeriodicalId":170873,"journal":{"name":"Australian Journal of Physics","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133665980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Nonlinear field-dependent susceptibilities of C 60 and carbon nanotubes c60和碳纳米管的非线性场相关磁化率
Australian Journal of Physics Pub Date : 1999-10-01 DOI: 10.1071/PH98098
M. F. Ling, T. Finlayson, C. Raston
{"title":"Nonlinear field-dependent susceptibilities of C 60 and carbon nanotubes","authors":"M. F. Ling, T. Finlayson, C. Raston","doi":"10.1071/PH98098","DOIUrl":"https://doi.org/10.1071/PH98098","url":null,"abstract":"We have found strongly nonlinear, field-dependent magnetic susceptibilities in a range of carbon-based materials such as C60, carbon nanotubes, diamond and graphite. This nonlinear behaviour is prominent at low fields and it vanishes at relatively high fields. We have interpreted this phenomenon in terms of the field dependence of the spectral energy separations of the van Vleck paramagnetic term of the susceptibility. Our results should have significant bearing on the interpretation of the magnetic properties of this class of materials.","PeriodicalId":170873,"journal":{"name":"Australian Journal of Physics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125794544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
Continuous localisation-delocalisation transition at intermediate electron densities 中等电子密度下的连续定域-离域跃迁
Australian Journal of Physics Pub Date : 1999-10-01 DOI: 10.1071/PH99060
D. Neilson, J. Thakur
{"title":"Continuous localisation-delocalisation transition at intermediate electron densities","authors":"D. Neilson, J. Thakur","doi":"10.1071/PH99060","DOIUrl":"https://doi.org/10.1071/PH99060","url":null,"abstract":"We find in 2D electron layers in quantum transistors that the interplay between the electron correlations and their interactions with defects in the semiconductor substrate generates a continuous localisation–delocalisation transition for intermediate electron densities (5 l rs l 9). We distinguish this transition from the discontinuous metal–insulator transition which is observed at lower electron densities (rs g 10). The approach we use is based on the behaviour of electrons at low densities. We take into account the interactions between electrons and also their interactions with disorder. We determine a zero temperature phase diagram of localised and delocalised states as a function of electron and impurity densities. The phase boundary of the continuous transition is determined by the localisation length of the electrons.","PeriodicalId":170873,"journal":{"name":"Australian Journal of Physics","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121422892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Ordered and disordered photonic band gap materials 有序和无序光子带隙材料
Australian Journal of Physics Pub Date : 1999-10-01 DOI: 10.1071/PH98110
R. McPhedran, L. Botten, A. Asatryan, N. Nicorovici, C. M. Sterke, P. Robinson
{"title":"Ordered and disordered photonic band gap materials","authors":"R. McPhedran, L. Botten, A. Asatryan, N. Nicorovici, C. M. Sterke, P. Robinson","doi":"10.1071/PH98110","DOIUrl":"https://doi.org/10.1071/PH98110","url":null,"abstract":"We discuss a formulation and computer implementation of a new method that can be used to determine the electromagnetic properties of ordered and disordered dielectric and metallic cylinders, using periodic boundary conditions in one direction. We show results which exhibit strong parallels with the behaviour of electrons in disordered semiconductors, but also illustrate some characteristics which clearly differentiate between photonic and electronic behaviour. Among these are strong polarisation sensitivity and effects due to metallic absorption.","PeriodicalId":170873,"journal":{"name":"Australian Journal of Physics","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121452133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 25
Equation-of-motion O(N) electronic structure studies of very large systems (N 运动方程O(N)非常大系统的电子结构研究(N)
Australian Journal of Physics Pub Date : 1999-10-01 DOI: 10.1071/PH99002
M. Michalewicz, P. Nyberg
{"title":"Equation-of-motion O(N) electronic structure studies of very large systems (N","authors":"M. Michalewicz, P. Nyberg","doi":"10.1071/PH99002","DOIUrl":"https://doi.org/10.1071/PH99002","url":null,"abstract":"Extremely fast parallel implementation of the equation-of-motion method for electronic structure computations is presented. The method can be applied to non-periodic, disordered nanocrystalline samples, transition metal oxides and other systems. It scales linearly, O(N), runs with a speed of up to 43 GFLOPS on a NEC SX-4 vector-parallel supercomputer with 32 processors and computes electronic densities of states (DOS) for multi-million atom samples in mere minutes. The largest test computation performed was for the electronic DOS for a TiO2 sample consisting of 7,623,000 atoms. Mathematically, this is equivalent to obtaining the spectrum of an n × n Hermitian operator (Hamiltonian) where n = 38;115; 000. We briefly discuss the practical implications of being able to perform electronic structure computations of this great speed and scale.","PeriodicalId":170873,"journal":{"name":"Australian Journal of Physics","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133627248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Observation of fractal conductance fluctuations over three orders of magnitude 三个数量级以上分形电导波动的观察
Australian Journal of Physics Pub Date : 1999-10-01 DOI: 10.1071/PH98108
Richard Taylor, A. Micolich, R. Newbury, T. Fromhold, C. Tench
{"title":"Observation of fractal conductance fluctuations over three orders of magnitude","authors":"Richard Taylor, A. Micolich, R. Newbury, T. Fromhold, C. Tench","doi":"10.1071/PH98108","DOIUrl":"https://doi.org/10.1071/PH98108","url":null,"abstract":"Fractal magneto-transport properties of mesoscopic semiconductor billiards are highly topical. In these studies, the magnetic field range over which fractal behaviour can be observed is crucial. Previous observations have been limited to approximately one order of magnitude. We present fractal conductance fluctuations observed over three orders of magnitude and discuss the physical conditions required to extend this range.","PeriodicalId":170873,"journal":{"name":"Australian Journal of Physics","volume":"180 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133303997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Experimental quantum ratchets based on solid state nanostructures 基于固体纳米结构的实验量子棘轮
Australian Journal of Physics Pub Date : 1999-10-01 DOI: 10.1071/PH99012
H. Linke
{"title":"Experimental quantum ratchets based on solid state nanostructures","authors":"H. Linke","doi":"10.1071/PH99012","DOIUrl":"https://doi.org/10.1071/PH99012","url":null,"abstract":"Ratchets are spatially asymmetric devices in which particles can move on average in one direction in the absence of external net forces or gradients. This is made possible by the rectification of fluctuations, which also provide the energy for the process. Interest in the physics of ratchets was revived in recent years when it emerged that the ratchet principle may be a suitable physical model for ‘molecular motors’, which are central to many fundamental biological processes, such as intracellular transport or muscle contraction. Most ratchets studied so far have relied on classical effects, but recently ‘quantum ratchets’, involving quantum effects, have also been studied. In the present article it is pointed out that semiconductor or metal nanostructures are very suitable systems for the realisation of experimental quantum ratchets. Recent experimental studies of a quantum ratchet based on an asymmetric quantum dot are reviewed.","PeriodicalId":170873,"journal":{"name":"Australian Journal of Physics","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126392020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
首页 上一页 下一页 尾页
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整，为了账户安全，请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们：info@booksci.cn Book学术提供免费学术资源搜索服务，方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号：481959085
Book学术官方微信