Einselection and the quantum to classical transition in quantum dots

Ferry, D. K.; Akis, R.; Bird, J. P.

doi:10.1088/0953-8984/17/13/001

Cited by 21 publications

(21 citation statements)

References 50 publications

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“…The decay of the correlation function with increasing ∆B is expected at low ∆B, reflecting the increasingly uncorrelated UCFs as ∆B increases, and figure 4 indeed shows that equation (2) provides a good fit at low ∆B. At higher ∆B the fit does not include the quasi-periodic oscillation visible in figure 4, also frequently observed in other work [30,37,40]. The quasi-periodic oscillation originates in a fluctuation in the density of states [31,40] related to pointer states [6,31].…”

Section: Experiments and Analysissupporting

confidence: 59%

“…At higher ∆B the fit does not include the quasi-periodic oscillation visible in figure 4, also frequently observed in other work [30,37,40]. The quasi-periodic oscillation originates in a fluctuation in the density of states [31,40] related to pointer states [6,31]. Under varying B the Fermi energy migrates through the energy levels of pointer states, which leads to oscillations in magnetoconductance, visible in the correlation function in figure 4.…”

Section: Experiments and Analysismentioning

confidence: 53%

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Geometrical dependence of quantum decoherence in circular arenas with side-wires

Xie

Priol

Heremans

2016

J. Phys.: Condens. Matter

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Low-temperature quantum phase coherence lengths were experimentally measured in mesoscopic circular arenas fabricated on InGaAs quantum wells. The arenas are connected to wide sample regions by short side-wires, to investigate the effects of geometry in comparison to intrinsic materials properties on quantum decoherence. Universal conductance fluctuations were used to quantify the phase coherence lengths as a function of temperature and geometry. The experimental data show a dependence of phase coherence lengths on side-wire length and width-to-length ratio, which is accounted for by the competing effects of decoherence by coupling to the classical environment and Nyquist decoherence in ergodic wires. The observed decay of phase coherence lengths with the increasing temperature is consistent with expectations. The work demonstrates that geometrical effects influence the measured mesoscopic quantum decoherence.

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Section: Experiments and Analysissupporting

confidence: 59%

Section: Experiments and Analysismentioning

confidence: 53%

Geometrical dependence of quantum decoherence in circular arenas with side-wires

Xie

Priol

Heremans

2016

J. Phys.: Condens. Matter

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“…Indeed, studies of the quantum pointer states have shown that they possess Poissonian statistics, representative of classical states [28,29]. Quantum mechanical calculations are based upon the same potential (found from self-consistent solutions), with the transport computed by a recursive scattering matrix formulation based upon the Lippman-Schwinger equation [30], and the conductance found from the Landauer equation [31].…”

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confidence: 99%

Transport in open quantum systems: comparing classical and quantum phase space dynamics

et al. 2008

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Transport in open quantum systems is of great interest. We show that the discrete states of an open quantum system may be classified into three distinct groups, dependent upon the manner in which they influence transport when connected to an external environment. A first class of states is current-carrying states, which are naturally strongly connected to the environment. A second class of states is discrete, but stable and isolated, and thought to be the pointer states of decoherence theory. Finally, we identify backscattered states, which do not propagate through the system. KeywordsOpen quantum systems · Conductance · Pointer states · ResonancesThe study of open quantum systems is important to gaining an understanding of how quantum states evolve into their classical counterparts [1]. This is particularly true in nanoelectronics devices, where the decoherence and phasebreaking processes are important. Such systems are open quantum systems interacting with their environment, the latter of which may be a bath or even a measurement system. The manner in which the quantum properties are revealed by such classical measurements, as well as the manner in which these quantum properties evolve into intrinsic classical properties, has long been of interest. One interpretation, which explicitly includes the coupling of the device to its environment, is decoherence theory [2]. However, the interpretation of the decoherence process has varied widely, and is crucially dependent upon the nature of the states that can exist within the device itself.In this paper, we show that the discrete states of an isolated quantum system may be classified into three groups, dependent upon the manner in which they influence transport when the system is opened. We show first that there is a class of current-carrying states, which are strongly connected to the environment. A second class of states is found to be a discrete set of stable, and isolated, states which are thought to be the so-called pointer states of decoherence theory [3]. (We have previously shown a connection to these pointer states in transport through open quantum dots [4].) We show how some of the current-carrying states can connect to the pointer states via phase-space tunneling processes to produce Fano resonances in the transmission. Finally, we identify backscattered states, which do not propagate through the system. We illustrate this with examples taken from experiments on a prototypical open quantum system, namely an open quantum dot array [5,6], which has been modeled both classically and quantum mechanically [7]. Such an array also connects to systems arising from periodic structures such as carbon nanotubes or molecules.Usually, transport through an open system is treated via electrodes configured as large reservoirs. However, we adopt a different approach that allows us to identify the connection between the quantum states of the open and closed system. Rather than treating the reservoirs in their normal sense, we introduce complex potentials at the contact regi...

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“…The importance here is that there has been achieved an amazing agreement between the simulated behavior of the transport and the experimental determination of the transport [19][20][21][22]. This close agreement between theory and experiment has allowed us to connect the physics of the quantum dot in a magnetic field to the theories of einselection [23] and the survival of pointer states [24] via quantum Darwinism [25][26][27].…”

Section: Discussionmentioning

confidence: 98%

Scattering matrix approach to direct solution of the Schrödinger equation

Akis

Ferry

2010

J Comput Electron

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We discuss a numerically stable method, the Usuki method, which is closely related to both the scattering matrix approach and recursive Green's functions. This approach provides a viable approach to directly solving the Schrödinger equation in simulations of semiconductor devices. It has a major advantage over the Green's function in that the electron density can be obtained far more efficiently for use in the self-consistent loop. Various applications of this approach have been studied, although here we focus upon the application of the method to study MOSFETS.

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Einselection and the quantum to classical transition in quantum dots

Cited by 21 publications

References 50 publications

Geometrical dependence of quantum decoherence in circular arenas with side-wires

Geometrical dependence of quantum decoherence in circular arenas with side-wires

Transport in open quantum systems: comparing classical and quantum phase space dynamics

Scattering matrix approach to direct solution of the Schrödinger equation

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