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Spin relaxation rates calculated using the exact diagonalization method. (a) Spin relaxation rates for |S N =2 (red), |Q +3/2 N =3 and |D +1/2 N =3 (blue), and |F +2 N =4 (green) as functions of excitation energy. (b) Same as (a) but for |F +2 N =4 and |S N =4 .
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We report the preparation and readout of multielectron high-spin states, a three-electron quartet, and a four-electron quintet, in a gate-defined GaAs/AlGaAs single quantum dot using spin filtering by quantum Hall edge states coupled to the dot. The readout scheme consists of mapping from multielectron to two-electron spin states and a subsequent t...
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... energy (meV) and |F +2 N =4 are faster than that of |S N =2 . Moreover, Fig. 4(b) shows that the relaxation of |F +2 N =4 is faster than that of |S N =4 [44], again in qualitative agreement with the experiment. These findings imply that electron correlation contributes to the fast relaxations of the high-spin states. The spin--orbit coupling strength may be enhanced by electron correlation through the increase in ...
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The concept of universality is a powerful tool in modern physics, allowing us to capture the essential features of a system's behavior using a small set of parameters. In this letter, we unveil universal spin relaxation dynamics in anisotropic random Heisenberg models with infinite-range interactions at high temperatures. Starting from a polarized...
Citations
... The consistent description thus requires the consideration of several orbitals of conduction electrons K > 1 which interact with the higher spin S > 1/2 of the localized magnetic impurity [8][9][10][11]. In addition, with the rapid progress of semiconductor quantum dot technology, the research on the understanding and controlling the properties of high-spin states is quickly expanding over last years with an ambition of using highspin states for quantum information processing [12]. ...
Quantum systems characterized by an interplay between several resonance scattering channels demonstrate very rich physics. To illustrate it we consider a multi-stage Kondo effect in nano-devices as a paradigmatic model for a multi-mode resonance scattering. We show that the channel cross-talk results in a destructive interference between the modes. This interplay can be controlled by manipulating the tunneling junctions in the multi-level and multi-terminal geometry. We present a full-fledged theory of the multi-stage Kondo effect at the strong coupling Fermi liquid fixed point and discuss the influence of quantum interference effects to the quantum transport observables.
Recent studies reveal that a double‐quantum‐dot system hosting more than two electrons may be superior in certain aspects as compared to the traditional case in which only two electrons are confined (a singlet–triplet qubit). The electron–phonon dephasing occurring in a GaAs multi‐electron double‐quantum‐dot system is studied, in a biased case in which the singlet state is hybridized, as well as in an unbiased case in which the hybridization is absent. It is found that while the electron–phonon dephasing rate increases with the number of electrons confined in the unbiased case, this does not hold in the biased case. A merit figure is defined as a ratio between the exchange energy and the dephasing rate, and have shown that in experimentally relevant range of the exchange energy, the merit figure actually increases with the number of electrons in the biased case. The results show that the multi‐electron quantum‐dot system has another advantage in mitigating the effect of electron–phonon dephasing, which is previously under‐appreciated in the literature.
In the paper we consider femtonanophotonics of the topological controlled low-dimensional dynamic structures in thin films induced by laser radiation on the surface of solids, using the achievements of quantum technologies and nonlinear dynamics for different regimes of electroconductivity.
We completed several laser procedures for obtaining nanostructures and thin films with controllable topology. They occur under the development of different nonlinear processes in the system (thermodiffusion, gas-dynamic evaporation in pore-like structures with bubbles, ablation products, ballistic movement of the particles in liquid). A simple 2-steps mechanism for enhancement of quantum behavior (e.g. in electroconductivity) exists for different conditions.
First, when inelastic length l inelastic > a cluster (size of cluster) we have no incoherent electron-phonon (e-ph) scattering, and coherent process occurs with scale ℓcoh.
Second, when de Broglie length λ dB ≡ ℓ coh > Λ (Λ – spatial period of the nanoparticle distribution) the coherent tunneling without loss occurs, and a long-range order with interference of the states takes place in the medium due to lattice structure in system.
Under such conditions, the electroconductivity enhancement can result in paradoxical phenomenon when electroconductivity in granulated structure may be higher than in monolith sample due to many surface/boundary units – like topological states in topological insulator.
Quantum systems characterized by an interplay between several resonance scattering channels demonstrate very rich physics. To illustrate it we consider a multistage Kondo effect in nanodevices as a paradigmatic model for a multimode resonance scattering. We show that the channel crosstalk results in a destructive interference between the modes. This interplay can be controlled by manipulating the tunneling junctions in the multilevel and multiterminal geometry. We present a full-fledged theory of the multistage Kondo effect at the strong-coupling Fermi-liquid fixed point and discuss the influence of quantum interference effects to the quantum transport observables.
