1,013 research outputs found
Transfer and storage of qubits in the presence of decoherence
The effects of decoherence on the transfer and storage of coherent quantum
states in hybrid systems are studied within the Caldeira-Leggett approach. In
general, we find that a high transfer fidelity can be achieved even if the
decoherence time is less than an order of magnitude larger than the transfer
time, which is approximately half a Rabi period and determined by the
qubit-qubit coupling strength. Finally, we apply our results to assess the
feasibility of a hybrid quantum memory system, comprised of the hyperfine qubit
states of an ultracold atomic Bose-Einstein condensate and the flux qubit of a
SQUID.Comment: 6 pages of EPL2, 3 figure
Tunneling into a Fractional Quantum Hall System and the Infrared Catastrophe
We calculate the tunneling density of states of a two-dimensional interacting
electron gas in a quantizing magnetic field. We show that the observed
pseudogap in the density of states can be understood as the result of an
infrared catastrophe in a noninteracting electron model. This catastrophe stems
from the response of an electronic system to the potential produced by the
abruptly added charge during a tunneling event. Our formalism can be applied at
any filling factor without the use of Chern-Simons or composite fermion theory
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