QMHP:: Decoherence, dissipation, entanglement and control in nanostructures.

QMHP：纳米结构中的退相干、耗散、纠缠和控制。在过去的十年里，电子器件变得越来越小，推动了技术的进步。为了提高计算机速度和计算机芯片的复杂性，需要更小的设备。继续这种趋势的可能性是有限的，因为技术已经接近达到原子水平。值得注意的是，在这个极限中，电子行为的不同规则，特别是量子现象，变得很重要。利用量子力学的定律，就有机会利用量子力学的相干性、电子波的干涉和纠缠。量子力学对象的链接使得一个对象不能在不知道其对应物的情况下被描述-用于开发新一代纳米器件。一个基本的挑战是理解和实现在电压下工作的器件中的量子现象，即，在非平衡条件下，以及在存在由于杂质原子引起的无序和波动的情况下，杂质原子在提供电荷载流子和限定电和磁性质方面起重要作用。量子现象受到相干性损失（退相干）的限制，有必要确定损失的机制并找到控制它们的方法。退相干将定义未来信息技术系统中每比特信息的耗散。旨在从理论上理解退相干和耗散的科学努力将集中在三个相互关联的项目上：1）吸收功率和拉比振荡（循环量子行为）在人造纳米级原子-量子点中，2）自旋引起的相干性损失（内禀量子角动量）和硅量子点中的电荷，3）磁性半导体纳米结构中的相干和输运理论，其可以在单个器件中结合联合收割机磁存储器和电子功能。智力价值：所提出的研究有望阐明量子器件中退相干的具体机制，并设计控制退相干和耗散的方法。虽然不是这项工作的唯一重点，但其结果可能有利于量子计算研究。所提出的方法有望克服在电压存在下处理时间相关量子行为的正式挑战，同时考虑到强相关性和纠缠效应。预期的分析结果将有可能影响未来量子器件的建模。更广泛的影响：拟议的研究具有潜在的社会效益，因为它旨在从根本上理解如何降低信息位的功耗，这是一个与器件小型化同样重要的趋势。对教育的影响将包括为研究生和高级本科生开设纳米科学课程，旨在培养未来的量子工程师，满足重要的社会需求。PI和通过拟议的计划资助的博士后研究员将积极参与与PI研究小组的研究生的不同群体的计划项目的讨论。与普渡大学物理系和伯克纳米技术中心网站链接的耗散和退相干专题网站将侧重于广泛传播预期的研究成果，以提高科学和技术的理解。

QMHP: Decoherence, dissipation, entanglement and control in nanostructures.Over the past decade, electronic devices have been getting smaller and smaller, driving the progress of technology. Smaller devices are desirable for improving computer speed and the complexity of computer chips. The possibility of continuing this trend is limited because technology is already close to reaching the atomic level. Remarkably, in this limit, different rules of electron behavior, particularly quantum phenomena, become important. Tapping the laws of quantum mechanics presents the opportunity of using quantum-mechanical coherence, interference of electronic waves, and entanglement ? linking of quantum mechanical objects so that one object cannot be described without knowledge of its counterpart - for developing a new generation of nanodevices.A fundamental challenge is the understanding and realization of quantum phenomena in devices which function under voltage, i.e., in non-equilibrium conditions, and in the presence of disorder and fluctuations due to impurity atoms that play an important role in supplying charge carriers and defining electric and magnetic properties. Quantum phenomena are limited by loss of coherence (decoherence), and it is necessary to identify mechanisms of losses and to find the means to control them. Decoherence will define dissipation per bit of information in future information technology systems.Scientific efforts directed at a theoretical understanding of decoherence and dissipation will be focused on three interconnected projects: 1) absorption of power and Rabi oscillations (cyclic quantum behavior) in artificial nanoscale atoms - quantum dots, 2) loss of coherence by spin (intrinsic quantum angular momentum) and charge in silicon quantum dots, 3) theory of coherence and transport in magnetic semiconductor nanostructures, which may combine magnetic memory and electronic functionalities in single devices.Intellectual merit: The proposed research holds a promise to elucidate specific mechanisms of decoherence in quantum devices and to devise methods to control decoherence and dissipation. Though not the sole focus of the work the results may benefit quantum computing research. The proposed approach promises to overcome formal challenges of treating time-dependent quantum behavior in the presence of voltage, taking into account strong correlations and entanglement effects. The expected analytical results will have a potential to affect the future modeling of quantum devices.Broader impacts: The proposed research has a potential benefit for society because it is aimed at developing a fundamental understanding of how to decrease power dissipation for bit of information, a trend as important as miniaturization of devices. The impact for education will include curriculum development in a nanoscience course for graduate students and advanced undergraduates, which aims at training of future quantum engineers, fulfilling an important societal need. Both the PI and a postdoctoral researcher funded via the proposed program will actively engage in discussions of the program projects with the diverse group of graduate students of the PI research group. A topical website on dissipation and decoherence linked to the Purdue Department of Physics and the Birck Nanotechnology Center websites will be focused on broad dissemination of the expected research results in order to enhance scientific and technological understanding.