Cooling of a Suspended Nanowire by an ac Josephson Current Flow

Sonne, Gustav; Peña-Aza, Milton E.; Gorelik, Leonid Y.; Shekhter, R. I.; Jonson, M.

doi:10.1103/physrevlett.104.226802

Cited by 37 publications

(47 citation statements)

References 20 publications

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“…Although very small, this back action may lead to interesting effects as the cooling effect of the mechanical degree of freedom in the presence of an external magnetic field. 28 Note also that we have safely neglected the effects of Coulomb blockade on the mechanical oscillation 37,38 since the interesting region for this device is the very transparent case.…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

Detection of ultrafast oscillations in superconducting point contacts by means of supercurrent measurements

2011

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We present a microscopic calculation of the nondissipative current through a superconducting quantum point contact coupled to a mechanical oscillator. Using the nonequilibrium Keldysh Green function approach, we determine the current-phase relation. The latter shows that at certain phases, the current is sharply suppressed. These dips in the current-phase relation provide information about the oscillating frequency and coupling strength of the mechanical oscillator. We also present an effective two-level model from which we obtain analytical expressions describing the position and width of the dips. Our findings are of relevance for nanomechanical resonators based on superconducting materials.

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Section: Discussion Of the Resultsmentioning

confidence: 99%

Detection of ultrafast oscillations in superconducting point contacts by means of supercurrent measurements

2011

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“…Taking into account that for the doubly clamped nanotube, ω 0 /ω n (n + 1) −2 and that ϕ 2n+1 (0) = 0, equation (9) indicates that the center-of-mass fluctuations are mainly defined by the average number of vibrons in the fundamental mode. Therefore, in order to suppress 7 such fluctuations, this number should have the minimum possible value.…”

Section: The Model Hamiltonianmentioning

confidence: 99%

“…laser cooling of atoms and molecules by purely electronic means [6][7][8][9]. The general strategy underlying these approaches is based on the coherent control of resonant, energy-conserving transitions between discrete electronic levels.…”

Section: Introductionmentioning

confidence: 99%

Suppression of the stochastic fluctuations of suspended nanowires by temperature-induced single-electron tunneling

et al. 2011

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Abstract. We theoretically investigate the electromechanical properties of freely suspended nanowires that are in tunneling contact with the tip of a scanning tunneling microscope (STM) and two supporting metallic leads. The aim of our analysis is to characterize the fluctuations of the dynamical variables of the nanowire when a temperature drop is maintained between the STM tip and the leads, which are all assumed to be electrically grounded. By solving a quantum master equation that describes the coupled dynamics of electronic and mechanical degrees of freedom, we found that the stationary state of the mechanical oscillator has a Gaussian character, but that the amplitude of its rootmean square center-of-mass fluctuations is smaller than would be expected if the system were coupled only to the leads at thermal equilibrium.

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“…7 In addition, new techniques for cooling mechanical motion have been proposed. 8,9 The use of superconducting devices, in particular, superconducting qubits to detect and control the mechanical motion is in focus of modern research. 7,10 It gives rise to a growing interest in techniques of coupling NEMS to superconducting circuits.…”

Section: Introductionmentioning

confidence: 99%

Effect of mechanical resonance on Josephson dynamics

2012

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We study theoretically dynamics in a Josephson junction coupled to a mechanical resonator looking at the signatures of the resonance in dc electrical response of the junction. Such a system can be realized experimentally as a suspended ultraclean carbon nanotube brought in contact with two superconducting leads. A nearby gate electrode can be used to tune the junction parameters and to excite mechanical motion. We augment theoretical estimations with the values of setup parameters measured in one of the samples fabricated. We show that charging effects in the junction give rise to a mechanical force that depends on the superconducting phase difference and can excite the resonant mode. We develop a model that encompasses the coupling of electrical and mechanical dynamics. We compute the mechanical response (the effect of mechanical motion) in the regime of phase and dc voltage bias. We thoroughly investigate the regime of combined ac and dc bias where Shapiro steps are developed and reveal several distinct regimes characteristic for this effect. Our results can be immediately applied in the context of experimental detection of the mechanical motion in realistic superconducting nanomechanical devices.

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Cooling of a Suspended Nanowire by an ac Josephson Current Flow

Cited by 37 publications

References 20 publications

Detection of ultrafast oscillations in superconducting point contacts by means of supercurrent measurements

Detection of ultrafast oscillations in superconducting point contacts by means of supercurrent measurements

Suppression of the stochastic fluctuations of suspended nanowires by temperature-induced single-electron tunneling

Effect of mechanical resonance on Josephson dynamics

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