Large-amplitude driving of a superconducting artificial atom

Oliver, William; Valenzuela, Sergio O.

doi:10.1007/s11128-009-0108-y

Cited by 46 publications

(43 citation statements)

References 95 publications

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“…As expected, higher [lower] decoherence rates lead to higher [lower] final phonon number. Note that in principle, Γ and Γ φ can be smaller by several orders of magnitude than γ in our system [6,27], leading to a cooling performance as in curve (ii) of Fig. 2.…”

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confidence: 89%

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Ground State Cooling of a Nanomechanical Resonator in the Nonresolved Regime via Quantum Interference

Xia

Evers

2009

Phys. Rev. Lett.

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Ground state cooling of a nanomechanical resonator coupled to a superconducting flux qubit is discussed. By inducing quantum interference to cancel unwanted heating excitations, ground state cooling becomes possible in the non-resolved regime. The qubit is modelled as a three-level system in Λ configuration, and the driving fluxes are applied such that the qubit absorption spectrum exhibits electromagnetically induced transparency, thereby cancelling the unwanted excitations. As our scheme allows to apply strong cooling fields, fast and efficient cooling can be achieved. and the observation of quantum mechanical phenomena in mesoscopic objects [1]. To fully utilize the properties of NAMRs or to observe mesoscopic quantum phenomena, it is typically necessary to cool the NAMR to the mechanical ground state. Thus it is not surprising that a number of different approaches for cooling micro-and nanomechanical resonators have been proposed theoretically [5][6][7][8][9][10] and also demonstrated experimentally [11][12][13][14][15][16][17]. For micromechanical resonators, cavity-assisted radiation pressure cooling has been intensely studied [1,8,11,17,18]. A different approach is active feedback cooling, which however typically requires difficult and precise measurements in real time of the displacement of the resonator [10,[13][14][15]. Cavitybased schemes are limited by diffraction, if the size of the resonator is small compared to the wavelength of the light. For NAMR, it has been proposed to achieve cooling by periodic coupling to a superconducting qubit (SQ) such as a Cooper pair box (CPB) [5] or to a three-level flux qubit [6]. Both techniques rely on a strong resonant interaction between resonators and the qubit. Recently, sideband cooling of micro-and nanomechanical resonators has attracted considerable interest. For example, cooling a NAMR has been proposed by embedding a quantum dot in the resonator [7], and it was observed in a microresonator [11] and in a transmission line resonator [9,16]. Also, a quantum theory of cooling has been developed [8].A number of problems associated with cooling NAMR are shared by laser cooling of atoms or ions. In particular, ground state sideband cooling is possible only in the resolved regime [8], in which the motional sidebands are resolved from the linewidth of the involved transitions [8,19]. This has been realized recently in few systems [16,18], but still this regime typically is difficult to achieve, and limits the accessible parameter range. To overcome this limit in atomic systems, a cooling scheme based on electromagnetically induced transparency (EIT) [20] has been proposed [21,22] and experimentally verified in ions [23]. EIT cooling works in the non-resolved regime, but suppresses the carrier excitation without change in the motional quantum number. This is achieved by designing the optical properties of the target system in such a way that absorption vanishes at the carrier transition frequency.In this Letter, we discuss ground state cooling of a NAMR in the non-r...

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“…The linewidth of state |a is given by γ = γ g + γ e . Since γ was not measured in [25], we assume γ = 50Γ [26,27]. As the final phonon number is insensitive to γ g /γ e , we choose γ g = γ e = γ/2.…”

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confidence: 99%

Ground State Cooling of a Nanomechanical Resonator in the Nonresolved Regime via Quantum Interference

Xia

Evers

2009

Phys. Rev. Lett.

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“…This in general induces accumulation of dynamical phases and superposition of wave functions leading thus to the formation of fringes that are inspected and probed in spectroscopic analyzes to capture some information relevant to the complex dynamics of a system bathing in its environment [5][6][7] . However, two crossings (double passage) might not be enough to produce desired information (an exceptional case of quantum interferences with a double-crossing configuration is discussed in Ref.…”

Section: Introductionmentioning

confidence: 99%

Periodically driven three-level systems

Kenmoe¹,

Fai²

2016

Phys. Rev. B

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We study the dynamics of a three-level system (ThLS) sinusoidally driven in both longitudinal and transverse directions and in the presence of a uniaxial anisotropy D entering the generic Hamiltonian through the zero-energy splitting term D(S z ) 2 where S z is the projection of the spin vector along the quantization direction. As a consequence of the addition of this term, the order of the symmetry group of the Hamiltonian is increased by a unit and we observe a sequence of cascaded SU (3) Landau-Zener-Stückelberg-Majorana (LZSM) interferometers. The study is carried out by analytically and numerically calculating the probabilities of non-adiabatic and adiabatic evolutions. For non-adiabatic evolutions, two main approximations based on the weak and strong driving limits are discussed by comparing the characteristic frequency of the longitudinal drive with the amplitudes of driven fields. For each of the cases discussed, our analytical results quite well reproduce the gross temporal profile of the exact numerical probabilities. This allows us to check the range of validity of analytical results and confirm our assumptions. For adiabatic evolutions, a general theory is constructed allowing for the description of adiabatic passages in arbitrary ThLSs in which direct transitions between states with extremal spin projections are forbidden. A compact formula for adiabatic evolutions is derived and numerically tested for some illustrative cases. Interference patterns demonstrating multiple LZSM transitions are reported. Applications of our results to the Nitrogen Vacancy Center (NVC) in diamond are discussed.

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“…When a periodic strong driving is applied to the qubit, the qubit undergoes repeated LZ transitions at the degeneracy point. If the driving frequency is larger than the decoherence rate, the repetition of LZ transitions can induce quantum interference, which leads to an oscillatory dependence of qubit population in the final state on the detuning from the degeneracy point and the microwave amplitude, known as LZS interferometry [18][19][20]26,[40][41][42][43][44][45][46][47][48][49][50].…”

Section: Introductionmentioning

confidence: 99%

Optimal cooling of a driven artificial atom in dissipative environment

Lan

2013

Low Temperature Physics

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We study microwave-driven cooling in a superconducting flux qubit subjected to environment noises. For the weak decoherence, our analytical results agree well with the experimental observations and show that the microwave amplitude for optimal cooling should depend linearly on the dc flux detuning. With the decoherence stronger, more vibrational degrees of freedom (analogous with atomic physics) couple in, making the ordinary cooling method less effective or even fail. We propose an improved cooling method, which can eliminate the perturbation of additional vibrational degrees of freedom hence keep high efficiency, even under the strong decoherence. Furthermore, we point out that the decoherence can tune the frequency where microwave-driven Landau-Zener transition reaches maximum, displaying the feature of incoherent dynamics which is important for the optimal cooling of qubits and other quantum systems.

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Large-amplitude driving of a superconducting artificial atom

Cited by 46 publications

References 95 publications

Ground State Cooling of a Nanomechanical Resonator in the Nonresolved Regime via Quantum Interference

Ground State Cooling of a Nanomechanical Resonator in the Nonresolved Regime via Quantum Interference

Periodically driven three-level systems

Optimal cooling of a driven artificial atom in dissipative environment

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