Detector backaction on the self-consistent bound state in quantum point contacts

Yoon, Young-Soo; Kang, Min-Sung; Morimoto, Takahiro; Mourokh, Lev G.; Aoki, Nobuyuki; Reno, John L.; Bird, J. P.; Ochiai, Y.

doi:10.1103/physrevb.79.121304

Cited by 22 publications

(72 citation statements)

References 29 publications

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“…Confirming that this feature is associated uniquely with physics that arises near pinch-off, no other resonances are observed as higher subbands of the swept QPC are subsequently populated. The resonance is reproduced, however, in devices with different gate configurations [22,24], in various QPCs fabricated on the same chip [24][25][26], and in multiple cooling cycles performed over a period of several years. From these collective observations, we are able to infer that the resonance does indeed result from the intrinsic properties of the QPC and is not a random-impurity effect.…”

Section: Bound-state Formation In Quantum Point Contactsmentioning

confidence: 97%

“…As illustrated schematically in Fig. 1, the two QPCs are coupled to each other through an intervening region of two-dimensional electron gas (2DEG), which provides the main means for their interaction [25]. The key observation in such experiments is that, as the swept QPC is pinched-off, an isolated resonance occurs in the detector conductance.…”

Section: Bound-state Formation In Quantum Point Contactsmentioning

confidence: 99%

“…1. Schematic illustration of the Fano resonance exhibited by a detector QPC that is coupled through a region of two-dimensional electron gas to a bound state in another QPC [22][23][24][25][26]. An electrochemical-potential difference between source and drain is used to drive electrons (thick red line) through the detector.…”

Section: Bound-state Formation In Quantum Point Contactsmentioning

confidence: 99%

“…The microscopic structure of this BS remains the subject of debate [35,36], however, so that further experiments are called for to confirm its existence. Utilizing the FR as a key signature of the presence of a discrete state, we have implemented a mesoscopic version of the FR experiment, in which the mutual interaction between a pair of coupled QPCs reveals the signature of the BS [22][23][24][25][26]. In these experiments, one QPC (the detector) is configured with fixed gate bias, while the gate voltage applied to the second (swept) QPC is varied continuously, driving it to pinch-off where BS formation is expected.…”

Section: Bound-state Formation In Quantum Point Contactsmentioning

confidence: 99%

“…Since our experimental demonstration of the continuummediated coupling is based on exploiting the specific properties of quantum point contacts (QPCs) near pinch-off, in Sec. II we first briefly review our recent work [22][23][24][25][26] in which we have shown how these structures may be used as an on-demand source of a localized quantum state. In Sec.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2012

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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.

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Section: Bound-state Formation In Quantum Point Contactsmentioning

confidence: 97%

Section: Bound-state Formation In Quantum Point Contactsmentioning

confidence: 99%

Section: Bound-state Formation In Quantum Point Contactsmentioning

confidence: 99%

Section: Bound-state Formation In Quantum Point Contactsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2012

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Dynamical stabilization and time in open quantum systems

Rotter

2012

Fortschritte der Physik

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The meaning of time in an open quantum system is considered under the assumption that both, system and environment, are quantum mechanical objects. The Hamilton operator of the system is non-Hermitian. Its imaginary part is the time operator. As a rule, time and energy vary continuously when controlled by a parameter. At high level density, where many states avoid crossing, a dynamical phase transition takes place in the system under the influence of the environment. It causes a dynamical stabilization of the system what can be seen in many different experimental data. Due to this effect, time is bounded from below: the decay widths (inverse proportional to the lifetimes of the states) do not increase limitless. The dynamical stabilization is an irreversible process. * rotter@pks.mpg.de

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Talking through the continuum: New manifestations of Fano‐resonance phenomenology realized with mesoscopic nanostructures

Xiao

Xiang

Yoon

et al. 2012

Fortschritte der Physik

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The focus of this review is recent work in which we have demonstrated a highly‐flexible approach to the study of Fano‐resonance phenomena, by making use of the mesoscopic devices known as quantum point contacts (QPCs). Utilizing the ability of these structures to function as an “on‐demand quantum state”, we demonstrate a highly‐flexible system for the investigation of Fano resonances. Our approach involves making measurements of non‐locally coupled pairs of QPCs, one of which is used to form the discrete state needed for the Fano resonance, while the other serves as a detector whose conductance is sensitive to the energy of this state. As a demonstration of the flexibility of this approach, we show how it can be used to implement a “multi‐state” Fano resonance, in which two discrete states undergo a robust interaction that is achieved by coupling them to each other through a common continuum.

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Detector backaction on the self-consistent bound state in quantum point contacts

Cited by 22 publications

References 29 publications

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

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

Dynamical stabilization and time in open quantum systems

Talking through the continuum: New manifestations of Fano‐resonance phenomenology realized with mesoscopic nanostructures

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