Showing papers by "Erik Lucero published in 2013"

Catch and release of microwave photon states.

Abstract: We demonstrate a superconducting resonator with variable coupling to a measurement transmission line. The resonator coupling can be adjusted through zero to a photon emission rate 1000 times the intrinsic resonator decay rate. We demonstrate the catch and release of photons in the resonator, as well as control of nonclassical Fock states. We also demonstrate the dynamical control of the release waveform of photons from the resonator, a key functionality that will enable high-fidelity quantum state transfer between distant resonators or qubits.

Excitation of superconducting qubits from hot nonequilibrium quasiparticles.

Abstract: Superconducting qubits probe environmental defects such as nonequilibrium quasiparticles, an important source of decoherence. We show that ``hot'' nonequilibrium quasiparticles, with energies above the superconducting gap, affect qubits differently from quasiparticles at the gap, implying qubits can probe the dynamic quasiparticle energy distribution. For hot quasiparticles, we predict a non-negligible increase in the qubit excited state probability ${P}_{e}$. By injecting hot quasiparticles into a qubit, we experimentally measure an increase of ${P}_{e}$ in semiquantitative agreement with the model and rule out the typically assumed thermal distribution.