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A microscopic theory of optical transitions in quantum dots with carrier-phonon interaction is developed. Virtual transitions into higher confined states with acoustic phonon assistance add a quadratic phonon coupling to the standard linear…

Condensed Matter · Physics 2009-11-10 E. A. Muljarov , R. Zimmermann

Phonon-assisted singlet-singlet relaxation in semiconductor quantum dot molecules is studied theoretically. Laterally coupled quantum dot structures doped with two electrons are considered. We take into account interaction with acoustic…

Mesoscale and Nanoscale Physics · Physics 2009-04-27 A. Grodecka , P. Machnikowski , J. Förstner

We theoretically compare transport properties of Fano-Kondo effect with those of Fano effect. We focus on shot noise characteristics of a triple quantum dot (QD) system in the Fano-Kondo region at zero temperature, and discuss the effect of…

Strongly Correlated Electrons · Physics 2015-05-13 Tetsufumi Tanamoto , Yoshifumi Nishi , Shinobu Fujita

In this work we study an effective three-mode model describing interacting bosons. These bosons can be considered as exciton-polaritons in a semiconductor microcavity at the magic angle. This model exhibits quantum phase transition (QPT)…

Quantum Physics · Physics 2018-01-19 H. M. Frazão , J. G. Peixoto de Faria , G. Q. Pellegrino , M. C. Nemes

We characterize the quantum gate fidelity in a state-independent manner by giving an explicit expression for its variance. The method we provide can be extended to calculate all higher order moments of the gate fidelity. Using these results…

Quantum Physics · Physics 2012-04-30 Easwar Magesan , Robin Blume-Kohout , Joseph Emerson

Feasibility study is done for the possibility of universal set of quantum gate implementation based on phononic state via 4th order Duffing nonlinearity in an optomechanical system. The optomechanical system consists of N doubly clamped…

Quantum Physics · Physics 2024-11-12 R. Alinaghipour , H. Mohammadi

In gate-defined quantum dot systems, the conductance change of electrostatically coupled sensor dots allows the observation of the quantum dots' charge and spin states. Therefore, the sensor dot must be optimally sensitive to changes in its…

Mesoscale and Nanoscale Physics · Physics 2025-08-12 Fabian Hader , Jan Vogelbruch , Simon Humpohl , Tobias Hangleiter , Chimezie Eguzo , Stefan Heinen , Stefanie Meyer , Stefan van Waasen

We investigate a superconducting qubit coupled to a quantum acoustic system in a near resonant configuration. In our system we measure multiphonon transitions, whose spectrum reveals distinctly nonclassical features and thus provides direct…

Mesoscale and Nanoscale Physics · Physics 2024-03-05 Alpo Välimaa , Wayne Crump , Mikael Kervinen , Mika A. Sillanpää

We show that the simultaneous interaction of two single-photon fields with a single atom in the V configuration can in principle produce a conditional phase gate of arbitrarily high fidelity, for an appropriate choice of the interaction…

Quantum Physics · Physics 2023-09-08 Arkan Hassan , Julio Gea-Banacloche

To achieve quantum computing using semiconductor spin qubits, the spin qubits must be precisely controlled. However, unexpected noise limits this precision and prevents the implementation of error correction codes. Specifically, frequency…

Mesoscale and Nanoscale Physics · Physics 2024-07-09 Yudai Sato , Takayuki Kawahara

A rate equation formalism is used to determine the effect of electron-phonon coupling on the conductance of a molecule. Interplay between the phonon-induced renormalization of the density of states on the quantum dot and the phonon-induced…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. Mitra , I. Aleiner , A. J. Millis

Echoes of quantum phase transitions (QPTs) at finite temperatures are theoretically and experimentally challenging and unexplored topics. Particularly in metallic quantum ferromagnets the experimental investigations are hampered by an…

We propose the implementation of fast resonant gates in circuit quantum electrodynamics for quantum information processing. We show how a suitable utilization of three-level superconducting qubits inside a resonator constitutes a key tool…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 G. Haack , F. Helmer , M. Mariantoni , F. Marquardt , E. Solano

In this paper, we propose a scheme to realize three-qubit quantum phase gate of one qubit simultaneously controlling two target qubits using four-level superconducting quantum interference devices (SQUIDs) coupled to a superconducting…

Quantum Physics · Physics 2015-06-12 Muhammad Waseem , Muhammad Irfan , Shahid Qamar

In this paper we present an experimentally realizable microwave pulse sequence that effects a Controlled NOT (C-NOT) gate operation on a Josephson junction-based flux-qubit/resonator system with high fidelity in the end state. We obtained a…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 S. Saito , T. Tilma , S. J. Devitt , K. Nemoto , K. Semba

In semiconductor quantum dots the coupling to the environment, i.e. to phonons, plays a crucial role for optical state preparation. We analyze the phonon impact on two methods for a direct optical preparation of the dark exciton, which is…

Mesoscale and Nanoscale Physics · Physics 2017-05-17 Sebastian Lüker , Tilmann Kuhn , Doris E. Reiter

Silicon nanomechanical resonators display ultra-long lifetimes at cryogenic temperatures and microwave frequencies. Achieving quantum control of single-phonons in these devices has so far relied on nonlinearities enabled by coupling to…

For a single semiconductor quantum dot embedded in a microcavity, we theoretically and experimentally investigate phonon-assisted transitions between excitons and the cavity mode. Within the framework of the independent boson model we find…

Mesoscale and Nanoscale Physics · Physics 2009-12-21 Ulrich Hohenester , Arne Laucht , Michael Kaniber , Norman Hauke , Abbas Mohtashami , Marek Seliger , Jonathan J. Finley

We observe a series of sharp resonant features in the tunnelling differential conductance of InAs quantum dots. We found that dissipative quantum tunnelling has a strong influence on the operation of nano-devices. Because of such tunnelling…

High-fidelity two-logical-qubit gates are essential for realizing fault-tolerant quantum computation with bosonic codes, yet experimentally reported fidelities have rarely exceeded 90\%. Here, we propose a geometric phase engineering…