Pumping and Cooling of Nanomechanical Vibrations Generated by Cooper-Pair Exchange

Ground state cooling of a nanomechanical resonator via a Cooper pair box qubit

In this paper we present a scheme for ground state cooling of a flexural mode of a nanomechanical beam incorporated in a loop-shaped Cooper-pair box (CPB) circuit. Via the Lorentz force coupling of the beam motion to circulating CPB-circuit currents, energy is transferred to the CPB qubit which acts as a dissipative two-level system. The cooling process is driven by a detuned gate-voltage drive...

Cooper-Pair Molasses - Cooling a Nanomechanical Resonator with Quantum Back-Action

Quantum mechanics demands that measurement must affect the measured object. When continuously monitoring position with a linear amplifier the Heisenberg uncertainty relationship requires that the object be driven by force impulses, called back-action 1,2,3. Here we report the detection of the measurement back-action of a superconducting single-electron transistor (SSET) which measures the posit...

Decoherence in adiabatic quantum evolution: application to cooper pair pumping.

One of the challenges of adiabatic control theory is the proper inclusion of the effects of dissipation. Here we study the adiabatic dynamics of an open two-level quantum system deriving a generalized master equation to consistently account for the combined action of the driving and dissipation. We demonstrate that in the zero-temperature limit the ground state dynamics is not affected by envir...

Superadiabatic theory for Cooper pair pumping under decoherence

Numerical study of energy loss by a nanomechanical oscillator coupled to a Cooper-pair box

We calculate the dynamics of a nanomechanical oscillator NMO coupled capacitively to a Cooper-pair box CPB by solving a stochastic Schrödinger equation with two Lindblad operators Commun. Math. Phys. 48, 119 1976 . . Both the NMO and the CPB are assumed dissipative, and the coupling is treated within the rotating wave approximation. We show numerically that, if the CPB decay time is smaller tha...