137 research outputs found
Cooling a magnetic resonance force microscope via the dynamical back-action of nuclear spins
We analyze the back-action influence of nuclear spins on the motion of the
cantilever of a magnetic force resonance microscope. We calculate the
contribution of nuclear spins to the damping and frequency shift of the
cantilever. We show that, at the Rabi frequency, the energy exchange between
the cantilever and the spin system cools or heats the cantilever depending on
the sign of the high-frequency detuning. We also show that the spin noise leads
to a significant damping of the cantilever motion.Comment: 15 pqges, 11 figures. The last part of Section IV.A and Section IV B
were rewritten. We added three new graphs: Figs. 5, 7, 9 and all graphs in
this subsection were recalculated for T=600 mK as in the experiment. Several
new references were adde
Resonance at the Rabi frequency in a superconducting flux qubit
We analyze a system composed of a superconducting flux qubit coupled to a
transmission-line resonator driven by two signals with frequencies close to the
resonator's harmonics. The first strong signal is used for exciting the system
to a high energetic state while a second weak signal is applied for probing
effective eigenstates of the system. In the framework of doubly dressed states
we showed the possibility of amplification and attenuation of the probe signal
by direct transitions at the Rabi frequency. We present a brief review of
theoretical and experimental works where a direct resonance at Rabi frequency
have been investigated in superconducting flux qubits. The interaction of the
qubit with photons of two harmonics has prospects to be used as a quantum
amplifier (microwave laser) or an attenuator.Comment: This paper is the extended version of the talk given by one of the
authors at the Conference On Nuclei And Mesoscopic Physics, 5-9 May 2014,
Michigan State University, East Lansing, US
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