52,705 research outputs found
Paired states of interacting electrons in a two dimensional lattice
We show that two tight binding electrons that repel may form a bounded pair
in two dimensions. The paired states form a band with energies that scale like
the strength of the interaction potential. By applying an electric field we
show that the dynamics of such states is that of a composite particle of charge
2e. The system still sustains Bloch-like states, so that if the two bands
overlap single and paired states might coexist allowing for a bosonic fluid
component that, if condensed, would decrease the resistance at low
temperatures. The presence of two bands allows for new oscillations whose
experimental detection would permit a direct measurement of the interaction
potential strength.Comment: 7 pages, 3 figure
Robustness of quantum discord to sudden death
We calculate the dissipative dynamics of two-qubit quantum discord under
Markovian environments. We analyze various dissipative channels such as
dephasing, depolarizing, and generalized amplitude damping, assuming
independent perturbation, in which each qubit is coupled to its own channel.
Choosing initial conditions that manifest the so-called sudden death of
entanglement, we compare the dynamics of entanglement with that of quantum
discord. We show that in all cases where entanglement suddenly disappears,
quantum discord vanishes only in the asymptotic limit, behaving similarly to
individual decoherence of the qubits, even at finite temperatures. Hence,
quantum discord is more robust than the entanglement against to decoherence so
that quantum algorithms based only on quantum discord correlations may be more
robust than those based on entanglement.Comment: 4 figures, 4 page
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