Strong correlation effects in mesoscopic systems

介观系统中的强相关效应

• 批准号: 250715-2006
• 负责人: LeHur, Karyn
• 金额: $ 2.72万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=336562
• 关键词: Strong; correlation; effects; mesoscopic; systems

A mesoscopic system is really like a large molecule (with a size between the nano and the micron), but in practice it is always, at least weakly, coupled to a much larger, essentially infinite, system. Ideally, one would like to interpolate between open and closed systems by varying some coupling strengths. The interest in investigating electron systems in the intermediate size range between microscopic and macroscopic, sometimes referred to as ''mesoscopic'' (a word coined by Van Kampen in 1981), is not only to understand the macroscopic limit and how it is achieved by, say, building up larger and larger clusters to go from the ''molecule'' to the ''bulk''; many novel phenomena exist that are intrinsic to mesoscopic systems. In fact, the special phenomena that exist in this mesoscopic range are of great interest by themselves. Many of the usual rules that one is used to in macroscopic physics may not hold in mesoscopic systems. For example, the rules for addition of resistances, both in series and in parallel, are different and more complicated. The electronic motion is definitely wavelike which emphasizes the importance of quantum mechanics. As a matter of fact, mesoscopic systems which behave like large artificial atoms are inevitably governed by "strong repulsion" effects between electrons resulting in a plethora of fascinating and unprecedented phenomena such as the Coulomb blockade effect allowing to build single-electron transistors, the appearance of excitations which eventually possess charges that are less than the elementary charge "e" of an electron, the so-called 0.7 anomaly occurring in conductance experiments through short quantum point contacts,... . Our theoretical proposal aims to predict novel physical laws governing mesoscopic electron systems that might stem from strong interaction effects, to understand properly the role of parasitic macroscopic degrees of freedom such as phonons or electromagnetic noise leading to quantum decoherence, to contrive novel solid-state settings that might produce and detect the entanglement between two artifical atoms or qubits, and finally by introducing Mechanics into this Quantum World by studying for instance how the vibrations of a nanodevice influence its transport properties.

介观系统实际上就像一个大分子（尺寸在纳米和微米之间），但实际上它总是与一个更大的、基本上无限的系统耦合，至少是微弱的耦合。理想情况下，人们希望通过改变一些耦合强度来在开放和封闭系统之间进行插值。研究介于微观和宏观之间的中等尺寸范围内的电子系统的兴趣，有时被称为“介观”。（这个词是由货车坎彭在1981年创造的），不仅是为了理解宏观极限，以及它是如何实现的，比如说，建立越来越大的集群，从“分子"到”大块“;存在许多新颖的现象，这些现象是介观系统所固有的。事实上，在这个介观范围内存在的特殊现象本身就很有趣。在宏观物理学中人们所习惯的许多通常规则在介观系统中可能不成立。例如，串联和并联的电阻相加的规则是不同的，并且更复杂。电子的运动肯定是波动的，这就强调了量子力学的重要性。事实上，表现得像大型人造原子的介观系统不可避免地受到电子之间的“强排斥”效应的控制，从而导致了大量迷人的和前所未有的现象，例如允许构建单电子晶体管的库仑阻塞效应，最终拥有小于电子基本电荷“e”的电荷的激发的出现，所谓的0.7异常发生在电导实验通过短量子点接触，. .我们的理论计划旨在预测可能源于强相互作用效应的介观电子系统的新物理定律，正确理解寄生宏观自由度（如声子或电磁噪声）导致量子退相干的作用，设计可能产生和检测两个人造原子或量子比特之间纠缠的新固态设置，最后，通过研究纳米器件的振动如何影响其传输特性，将力学引入量子世界。