Quantum electron splitter based on two quantum dots attached to leads

Malyshev, A. V.; Orellana, P. A.; Domı́nguez-Adame, F.

doi:10.1103/physrevb.74.033308

Cited by 15 publications

(8 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While one often views the continuum as a source of decoherence, our work therefore suggests the possibility of using this medium to support the interaction of quantum states, a result that has the potential of opening up new approaches to coherently couple nanostructures in complex geometries. The nonlocal coupling considered here has been proposed, for example, as a means to achieve an electronic analog of the Dicke effect [16,45], a wellknown effect in quantum optics [46,47] in which superradiance arises when a photon field mediates the interaction of excited atoms. Our demonstration of extended-molecule formation demonstrates the potential of realizing new electronic devices by transferring concepts from quantum optics.…”

Section: Discussionmentioning

confidence: 99%

“…In addition to the technological importance of this issue, this approach provides an invaluable way to explore quantum-mechanical interactions at the microscopic level, with a control that is simply not possible in conventional atomic systems. There have been numerous reports [10][11][12][13][14][15][16][17][18], for example, concerning the use of quantum dots as artificial atoms, providing a highly tunable system for investigations of new aspects of FR phenomenology (see the reviews of Refs. [19,20]).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Coupling Quantum States through a Continuum: A Mesoscopic Multistate Fano Resonance

et al. 2012

View full text Add to dashboard Cite

We demonstrate a fully tunable realization of a multistate Fano resonance, in which a pair of remote quantum states experience an effective coupling due to their mutual overlap with a continuum. Our mesoscopic implementation of this system exploits the ability of the semiconductor nanostructures known as quantum point contacts (QPCs) to serve, in the low-density limit close to pinch-off, as an on-demand localized state. By coupling the states formed on two separate QPCs, through a two-dimensional electron gas that serves as a continuum, we observe a robust effective interaction between the QPCs. To explain this result, we develop a theoretical formulation, based on the ideas of the Schrieffer-Wolff transformation, which is able to reproduce our key experimental findings. According to this model, the robust character of the interaction between the two remote states arises from the fact that the interaction is essentially mediated by a large number of degenerate continuum states. While the continuum is often viewed as a source of decoherence, our experiment therefore instead suggests the possibility of using this medium to support the interaction of quantum states, a result that may allow new approaches to coherently couple nanostructures in extended geometries.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Coupling Quantum States through a Continuum: A Mesoscopic Multistate Fano Resonance

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Given the experiment of Kobayashi et al [3] with sidecoupled dots and the high tunability of double quantum dots we hope our result will stimulate a similar setup with a charge detector. We mention also a recent paper by Malyshev et al [7] on non-interacting side-coupled double dots which presents the time evolution of an incoming narrow Gaussian packet. The theoretical formulation we have previously developed [2] and briefly discussed here should be applicable to this and similar systems.…”

Section: Resultsmentioning

confidence: 88%

Coherent and incoherent transport through T-shaped double quantum dots

Moldoveanu

Ţolea

Tanatar

2008

Physica E: Low-dimensional Systems and Nanostructures

View full text Add to dashboard Cite

We investigate the measurement induced dephasing of the Fano effect in the electronic transport through a double quantum dot mesoscopic interferometer coupled to a charge detector. The current and the differential conductance are computed within the Keldysh formalism, taking into account of the inelastic processes due to the dot-detector interaction. We show that the visibility of the Fano lineshape is reduced by applying a finite bias on the charge detector. © 2007 Elsevier B.V. All rights reserved

show abstract

“…As shown in Ref. [27], when ∆ ≪ Γ, as in (b) and (c), the DOS can be approached by a sum of two Lorentzians of widths Γ + = 2Γ and Γ − = ∆ 2 /2Γ centered at ε 0 . In summary, for any of the considered systems, the density of states when Γ − → 0 can be written as a superposition of a Lorentzian and a Dirac delta function…”

mentioning

confidence: 78%

Friedel phase discontinuity and bound states in the continuum in quantum dot systems

Solís¹,

Guevara²,

Orellana³

2008

Physics Letters A

View full text Add to dashboard Cite

In this article we study the Friedel phase of the electron transport in two different systems of quantum dots which exhibit bound states in the continuum (BIC). The Friedel phase jumps abruptly in the energies of the BICs, which is associated to the vanishing width of these states, as shown by Friedrich and Wintgen in Phys. Rev. A 31, 3964 (1985). This odd behavior of the Friedel phase has consequences in the charge through the Friedel sum rule. Namely, if the energy of the BIC drops under the Fermi energy the charge changes abruptly in a unity. We show that this behavior closely relates with discontinuities in the conductance predicted for interacting quantum dot systems. In a early work, von Neumann and Wigner [1] showed that for certain local potentials, the Schrödinger equation has exact solutions with energy eigenvalues above the continuum threshold. These potentials can be constructed in one dimension by a method suggested in the same article. Much later, several theoretical and experimental works show the existence of these "bound states in the continuum" (BICs) in different contexts. In Ref.[2] it is shown that these states can occur in a system of coupled square well potentials for appropriate values of the well depths and coupling strengths. Stillinger and Herrick corrected and extended von Neumann work to consider systems in two dimensions [3], constructing some potentials leading to BICs. Friedrich and Wintgen demonstrated that BICs occur in natural way, not only for specific potentials, when two resonances associated with different channels interfere [4]. In transport through mesoscopic and nanoscopic systems, there are theoretical works showing the formation of these states in a four-terminal junction [5], in a ballistic channel with intersections [6], and more recently, bound states in the continuum have been theoretically discussed for systems of quantum dots [7,8,9,10] The density of states (DOS) is of great relevance to understand transport phenomena. The DOS is related to the scattering matrix S via the Friedel sum rule (FSR), which can be stated aswhere the Friedel phase θ F is defined aswhere the phase shifts ξ l are obtained from the eigenvalues of the scattering matrix S, λ l = e 2iξ l [14,15]. The FSR has been central in the understanding of the behavior of impurities in metals [16], but recently has received considerable attention in the context of low dimensional systems [15,17,18,19,20,21]. Relations between the Friedel phase and properties such as resistance [22], persistent current [23], and capacitance [24] have been studied.As emphasized by Lee [17] and Taniguchi and Büttiker [15], it is not correct to identify the Friedel phase (2) with the phase of the amplitude of transmission. Ref. [15] studies the connection between the Friedel phase and the transmission phase in scattering systems in mesoscopic physics. It is shows that the transmission phase can change abruptly in π while the Friedel phase remains continuous as a function of the energy. The transmission phase discontinuity ...

show abstract

Quantum electron splitter based on two quantum dots attached to leads

Cited by 15 publications

References 11 publications

Coupling Quantum States through a Continuum: A Mesoscopic Multistate Fano Resonance

Coupling Quantum States through a Continuum: A Mesoscopic Multistate Fano Resonance

Coherent and incoherent transport through T-shaped double quantum dots

Friedel phase discontinuity and bound states in the continuum in quantum dot systems

Contact Info

Product

Resources

About