Microwave spectroscopy on a double quantum dot with an on-chip Josephson oscillator

Holleitner, Alexander W.; Qin, Hua; Simmel, Friedrich C.; Irmer, Bernd; Blick, Robert H.; Kotthaus, J. P.; Ustinov, A. V.; Eberl, K.

doi:10.1088/1367-2630/2/1/302

Cited by 11 publications

(15 citation statements)

References 30 publications

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“…(27), keeps the energy difference to the excited state |+ constant throughout the adiabatic rotation. In this case, it follows that the dissipative contribution to δ σ z f , Eq.…”

Section: Discussionmentioning

confidence: 99%

“…1) with constant energy difference ∆ to the excited state ε + . For the particular sinusoidal form T c (t) = − ∆ 2 sin Ωt, ε(t) = −∆ cos Ωt (27) of T c (t) and ε(t), the time-dependent Hamiltonian…”

Section: A Transfer Rate: Exact Solution For Rabi Rotation and Weak mentioning

confidence: 99%

“…The cycle starts with an additional electron in the left dot and an adiabatic rotation of the parameters (ε(t), T c (t)) such as, e.g., in Eq. (27) or in Eq. (2), cf.…”

Section: Adiabatic Quantum Pumping In Open Double Dotsmentioning

confidence: 99%

“…Furthermore, in the strong Coulomb blockade regime of coupled quantum dots, the non-adiabatic coupling to AC fields in photo-assisted transport 9,22-24 has been established in experiments [25][26][27] . In the opposite regime of weak Coulomb correlations, experiments in open dots 28 have demonstrated the feasability of an 'adiabatic quantum electron pump'.…”

Section: Introductionmentioning

confidence: 99%

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Adiabatic transfer of electrons in coupled quantum dots

2002

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We investigate the influence of dissipation on one-and two-qubit rotations in coupled semiconductor quantum dots, using a (pseudo) spin-boson model with adiabatically varying parameters. For weak dissipation, we solve a master equation, compare with direct perturbation theory, and derive an expression for the 'fidelity loss' during a simple operation that adiabatically moves an electron between two coupled dots. We discuss the possibility of visualizing coherent quantum oscillations in electron 'pump' currents, combining quantum adiabaticity and Coulomb blockade. In two-qubit spin-swap operations where the role of intermediate charge states has been discussed recently, we apply our formalism to calculate the fidelity loss due to charge tunneling between two dots.

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“…(27), keeps the energy difference to the excited state |+ constant throughout the adiabatic rotation. In this case, it follows that the dissipative contribution to δ σ z f , Eq.…”

Section: Discussionmentioning

confidence: 99%

Section: A Transfer Rate: Exact Solution For Rabi Rotation and Weak mentioning

confidence: 99%

“…The cycle starts with an additional electron in the left dot and an adiabatic rotation of the parameters (ε(t), T c (t)) such as, e.g., in Eq. (27) or in Eq. (2), cf.…”

Section: Adiabatic Quantum Pumping In Open Double Dotsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Adiabatic transfer of electrons in coupled quantum dots

2002

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“…Such superpositions would constitute a qubit basis in an artificial semiconductor structure that can be coupled to the external world by leads and therefore be accessed by transport spectroscopy. Transport experiments have already successfully revealed a number of quantum coherent effects due to static potential coupling [1][2][3] or coupling to microwave radiation [4][5][6] in double quantum dots, and their use as qubits that are controlled by gate-voltages or magnetic fields has been suggested 7 recently. Unfortunately, at present there are no data at all for dephasing rates γ of superpositions |Ψ f in such systems.…”

Section: Introductionmentioning

confidence: 99%

Adiabatic steering and determination of dephasing rates in double-dot qubits

2001

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We propose a scheme to prepare arbitrary superpositions of quantum states in double quantum-dots irradiated by coherent microwave pulses. Solving the equations of motion for the dot density matrix, we find that dephasing rates for such superpositions can be quantitatively infered from additional electron current pulses that appear due to a controllable breakdown of coherent population trapping in the dots.73.21. La, 32.80.Qk, 85.35.Gv

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Macroscopic Quantum Effects in the Resistive States of Josephson Coupled Systems

Fistul

2002

phys. stat. sol. (b)

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In this report I present a theoretical study of macroscopic quantum coherent effects in the resistive (whirling) state of dc driven Josephson junction arrays. The current-voltage characteristics of such systems display resonant steps that are due to the resonant interaction between the time dependent Josephson current and the excited electromagnetic oscillations (EOs). The voltage positions of the resonances are determined by the transitions between the discrete energy levels in the spectrum of EOs. We show that in the quantum regime as the system is driven on the resonance, coherent Rabi oscillations between the quantum levels of EOs occur. At variance with the classical regime the magnitude and the width of resonances are determined by the incoherent relaxation processes or the frequency of Rabi oscillations that in turn, depends on an externally applied magnetic field and the parameters of the system. Various quantum effects predicted and observed in macroscopic systems [1-10] have attracted a great attention as it allows to understand the foundation of quantum mechanics [1] and the applicability of quantum mechanics to dissipative systems [10][11][12]. The interest to this field has been also boosted by the possibility to use macroscopic quantum coherent effects for quantum computation [4,[6][7][8][9]13].In this field of study Josephson coupled systems consisting of a few interacting Josephson junctions, are of special interest. These systems contain a large number of particles and still, their behaviour is determined by the macroscopic variables, namely Josephson phases j i ðtÞ. Moreover, the dynamics of Josephson phases can be controlled by an externally applied magnetic field H ext and dc bias g, and at low temperatures the number of quasi-particles is extremely small and therefore, the dissipation caused by the quasi-particle current is also small. Moreover, a recent observation of time domain quantum coherent oscillations (the Rabi oscillations) in various Josephson systems [7][8][9] has shown that other sources of dissipation, e.g. fluctuations of the bias current and a charge noise can be also suppressed.The majority of macroscopic quantum effects have been studied as the Josephson junctions were biased in the superconducting state, i.e. zero dc voltage state, and the quantum mechanical behaviour of the resistive state of Josephson coupled systems has not been analyzed. It is also well known that the resistive state of Josephson coupled systems presents a whirling state as the Josephson phase j i ðtÞ across the whirling junction increases in time [14]. In the whirling state a measured dc voltage V is determined by a time averaged value of _ j j i ðtÞ, and intrinsic Josephson current oscillations of the frequency w / V occur in a system. In a classical regime this oscillating Josephson current can excite the electromagnetic oscillations (EOs), i.e. the Josephson phase and superconducting current oscillations in the superconducting loops, and in turn, these phys. stat. sol. (b) 233, No. 3, 497-505 (2002)...

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Microwave spectroscopy on a double quantum dot with an on-chip Josephson oscillator

Cited by 11 publications

References 30 publications

Adiabatic transfer of electrons in coupled quantum dots

Adiabatic transfer of electrons in coupled quantum dots

Adiabatic steering and determination of dephasing rates in double-dot qubits

Macroscopic Quantum Effects in the Resistive States of Josephson Coupled Systems

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