|
| related topics |
| {energy, state, states} |
| {time, decoherence, evolution} |
| {qubit, qubits, gate} |
| {equation, function, exp} |
| {spin, pulse, spins} |
| {cos, sin, state} |
| {wave, scattering, interference} |
| {time, wave, function} |
| {entanglement, phys, rev} |
| {bell, inequality, local} |
| {level, atom, field} |
|
Two-particle localization and antiresonance in disordered spin and qubit
chains
L. F. Santos, M. I. Dykman
abstract: We show that, in a system with defects, two-particle states may experience
destructive quantum interference, or antiresonance. It prevents an excitation
localized on a defect from decaying even where the decay is allowed by energy
conservation. The system studied is a qubit chain or an equivalent spin chain
with an anisotropic ($XXZ$) exchange coupling in a magnetic field. The chain
has a defect with an excess on-site energy. It corresponds to a qubit with the
level spacing different from other qubits. We show that, because of the
interaction between excitations, a single defect may lead to multiple localized
states. The energy spectra and localization lengths are found for
two-excitation states. The localization of excitations facilitates the
operation of a quantum computer. Analytical results for strongly anisotropic
coupling are confirmed by numerical studies.
- oai_identifier:
- oai:arXiv.org:quant-ph/0303130
- categories:
- quant-ph cond-mat
- comments:
- Updated version, 13 pages, 5 figures To appear in Phys. Rev. B (2003)
- doi:
- 10.1103/PhysRevB.68.214410
- arxiv_id:
- quant-ph/0303130
- created:
- 2003-03-20
- updated:
- 2003-11-12
Full article ▸
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