137 research outputs found
Fluorescence interferometry
We describe an interferometer based on fluorescent emission of radiation of
two qubits in quasi-one-dimensional modes. Such a system can be readily
realized with dipole emitters near conducting surface-plasmonic nanowires or
with superconducting qubits coupled to coplanar waveguide transmission lines.Comment: 7 pages, 2 figure
How Do Schr\"odinger's Cats Die?
Recent experiments with superconducting qubits are motivated by the goal of
fabricating a quantum computer, but at the same time they illuminate the more
fundamental aspects of quantum mechanics. In this paper we analyze the physics
of switching current measurements from the point of view of macroscopic quantum
mechanics.Comment: 4 figures, 12 page
Cross-coupling effects in circuit-QED stimulated Raman adiabatic passage
Stimulated Raman adiabatic passage is a quantum protocol that can be used for
robust state preparation in a three-level system. It has been commonly employed
in quantum optics, but recently this technique has drawn attention also in
circuit quantum electrodynamics. The protocol relies on two slowly varying
drive pulses that couple the initial and the target state via an intermediate
state, which remains unpopulated. Here we study the detrimental effect of the
parasitic couplings of the drives into transitions other than those required by
the protocol. The effect is most prominent in systems with almost harmonic
energy level structure, such as the transmon. We show that under these
conditions in the presence of decoherence there exists an optimal STIRAP
amplitude for population transfer.Comment: Will be published in proceedings for 28th International Conference
for Low Temperature Physic
Evolution of fragmented states
We consider the problem of evolution of the many-body state of a weakly
interacting system of bosons in an initially fragmented (Fock) state. We show
that the state at any time can be expressed as a continuous superposition of an
infinite number of Gross-Pitaevskii states.Comment: 4 page
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