366 citations · 642 across the 7 of their papers we have counts for
7 papers
High coherence hybrid superconducting qubit
Matthias Steffen, Shwetank Kumar, David P. DiVincenzo +4
We measure the coherence of a new superconducting qubit, the {\em low-impedance flux qubit}, finding s. It is a three-junction flux qubit, but the ratio o…
Superconducting resonators as beam splitters for linear-optics quantum computation
Luca Chirolli, Guido Burkard, Shwetank Kumar +1
A functioning quantum computer will be a machine that builds up, in a programmable way, nonclassical correlations in a multipartite quantum system. Linear optics quantum computatio…
Readout for Phase Qubits without Josephson Junctions
Matthias Steffen, Shwetank Kumar, David DiVincenzo +4
We present a novel readout scheme for phase qubits which eliminates the read-out SQUID so that the entire qubit and measurement circuitry only requires a single Josephson junction.…
Exploiting Kerr Cross Non-linearity in Circuit Quantum Electrodynamics for Non-demolition Measurements
Shwetank Kumar, David P. DiVincenzo
We propose a scheme for dispersive readout of stored energy in one mode of a nonlinear superconducting microwave ring resonator by detection of the frequency shift of a second mode…
Decoherence of floating qubits due to capacitive coupling
Matthias Steffen, Frederico Brito, David DiVincenzo +2
It has often been assumed that electrically floating qubits, such as flux qubits, are immune to decoherence due to capacitive coupling. We show that capacitive coupling to bias lea…
Experimental evidence for a surface distribution of two-level systems in superconducting lithographed microwave resonators
Jiansong Gao, Miguel Daal, Peter Day +6
We present measurements of the temperature-dependent frequency shift of five niobium superconducting coplanar waveguide microresonators with center strip widths ranging from 3 m…