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Superconducting, flux-based qubits are promising candidates for the construction of a large scale quantum computer. We present an explicit quantum mechanical calculation of the coherent behavior of a flux based quantum bit in a noisy…

Quantum Physics · Physics 2007-05-23 Jonathan L. Habif , Mark F. Bocko

We propose to use the phenomenon of resonant tunneling for the detection of noise. The main idea of this method relies on the effect of homogeneous broadening of the resonant tunneling peak induced by the emission and absorption of…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Eugene V. Sukhorukov , Jonathan Edwards

The electronic transport of a noninteracting quantum ring side-coupled to a quantum wire is studied via a single-band tunneling tight-binding Hamiltonian. We found that the system develops an oscillating band with antiresonances and…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 P. A. Orellana , M. L. Ladron de Guevara , M. Pacheco , A. Latge

We study spin-resolved resonant tunneling in a system of two quantum dots sandwiched between doped quantum wells. In the coherent (Dicke) regime, i.e., when quantum dot separation is smaller than the Fermi wavelength in a two-dimensional…

Mesoscale and Nanoscale Physics · Physics 2019-04-15 L. S. Petrosyan , T. V. Shahbazyan

Quantum mechanical effects induced by the miniaturization of complementary metal-oxide-semiconductor (CMOS) technology hamper the performance and scalability prospects of field-effect transistors. However, those quantum effects, such as…

We study the dynamics of a symmetric two-level system strongly coupled to a broadened harmonic mode. Upon mapping the problem onto a spin-boson model with peaked spectral density, we show how analytic solutions can be obtained, at arbitrary…

Statistical Mechanics · Physics 2009-11-13 F. Nesi , M. Grifoni , E. Paladino

We present exact results on the non-equilibrium current fluctuations for 2 quantum dots in series throughout a crossover from non-Fermi liquid to Fermi liquid behavior described by the 2 impurity Kondo model. The result corresponds to…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Eran Sela , Ian Affleck

We present a theoretical analysis of the capacitance of a double quantum dot in the charge and spin qubit configurations probed at high-frequencies. We find that in general the total capacitance of the system consists of two state-dependent…

Mesoscale and Nanoscale Physics · Physics 2017-01-25 R. Mizuta , R. M. Otxoa , A. C. Betz , M. F. Gonzalez-Zalba

We analyze the response of a complex quantum-mechanical system (e. g., a quantum dot) to a time-dependent perturbation. Assuming the dot energy spectrum and the perturbation to be described by the Gaussian Orthogonal Ensemble of random…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 D. M. Basko , M. A. Skvortsov , V. E. Kravtsov

We use time-resolved charge detection techniques to investigate single-electron tunneling in semiconductor quantum dots. The ability to detect individual charges in real-time makes it possible to count electrons one-by-one as they pass…

Mesoscale and Nanoscale Physics · Physics 2009-05-29 S. Gustavsson , R. Leturcq , M. Studer , I. Shorubalko , T. Ihn , K. Ensslin , D. C. Driscoll , A. C. Gossard

We study entanglement dynamics in a system consisting of a qubit dispersively coupled to a finite-temperature, dissipative, driven oscillator. We show that there are two generic ways to generate entanglement: one can entangle the qubit…

Mesoscale and Nanoscale Physics · Physics 2008-10-24 D. W. Utami , A. A. Clerk

We present a comprehensive theoretical investigation on the dynamic electronic response of a noninteracting quantum dot system to various forms of time-dependent voltage applied to the single contact lead. Numerical simulations are carried…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Xiao Zheng , Jinshuang Jin , YiJing Yan

Quantum annealing is a method to solve optimization problems that leverages quantum tunneling in a coupled qubit system. We present a detailed study of the coherence of a tunable capacitively-shunted flux qubit, designed for coherent…

We report on spectroscopic and time-domain measurements on a fixed-frequency concentric transmon qubit in an applied in-plane magnetic field to explore its limits of magnetic field compatibility. We demonstrate quantum coherence of the…

We consider a qubit coupled to a nonlinear quantum oscillator, the latter coupled to an Ohmic bath, and investigate the qubit dynamics. This composed system can be mapped onto that of a qubit coupled to an effective bath. An approximate…

Quantum Physics · Physics 2015-05-20 Carmen Vierheilig , Dario Bercioux , Milena Grifoni

The dissipative dynamics of two interacting qubits coupled to independent reservoirs at nonzero temperatures is investigated, paying special attention to the entanglement evolution. The counter-rotating terms in the qubit-qubit interaction…

Quantum Physics · Physics 2015-05-13 M. Scala , R. Migliore , A. Messina , L. L. Sanchez-Soto

A theory is developed for the emission noise at frequency $\nu$ in a quantum dot in the presence of Coulomb interactions and asymmetric couplings to the reservoirs. We give an analytical expression for the noise in terms of the various…

Mesoscale and Nanoscale Physics · Physics 2018-03-15 A. Crépieux , S. Sahoo , T. Q. Duong , R. Zamoum , M. Lavagna

Using time-resolved transconductance spectroscopy, we study the tunneling dynamics between a two-dimensional electron gas (2DEG) and self-assembled quantum dots (QDs), embedded in a field-effect transistor structure. We find that the…

Mesoscale and Nanoscale Physics · Physics 2014-05-26 Andreas Beckel , Annika Kurzmann , Martin Geller , Arne Ludwig , Andreas D. Wieck , Jürgen König , Axel Lorke

The decoherence of a two-state system coupled with a sub-Ohmic bath is investigated theoretically by means of the perturbation approach based on a unitary transformation. It is shown that the decoherence depends strongly and sensitively on…

Quantum Physics · Physics 2017-07-10 Zhiguo Lü , Hang Zheng

We theoretically investigate the non-equilibrium quantum dynamical theory of a quantum dot system coupled to fermionic reservoirs using the recently developed stochastic fermionic quantum state diffusion (FQSD) equation. The exact or…

Quantum Physics · Physics 2018-12-07 Wufu Shi , Yusui Chen , Lihui Sun , J. Q. You , Ting Yu