Suppression of decoherence and disentanglement by the exchange interaction

Journal Article · Fri Apr 15 04:00:00 EDT 2011 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.83.042331· OSTI ID:21544598

De, Amrit; Lang, Alex; Dong, Zhou; Joynt, Robert ^[1]

---

1. Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)

Entangled qubit pairs can serve as a quantum memory or as a resource for quantum communication. The utility of such pairs is measured by how long they take to disentangle or decohere. To answer the question of whether qubit-qubit interactions can prolong entanglement, we calculate the dissipative dynamics of a pair of qubits coupled via the exchange interaction in the presence of random telegraph noise and 1/f noise. We show that for maximally entangled (Bell) states, the exchange interaction generally suppresses decoherence and disentanglement. This suppression is more apparent for random telegraph noise if the noise is non-Markovian, whereas for 1/f noise the exchange interaction should be comparable in magnitude to the strongest noise source. The entangled singlet-triplet superposition state of two qubits ({psi}{sub {+-}} Bell state) can be protected by the interaction, while for the triplet-triplet state ({phi}{sub {+-}} Bell state), it is less effective. Thus the former is more suitable for encoding quantum information.

• OSTI ID: 21544598
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 83; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMMUNICATIONS
DATA TRANSMISSION
EXCHANGE INTERACTIONS
INFORMATION
INTERACTIONS
MARKOV PROCESS
MULTIPLETS
NOISE
QUANTUM ENTANGLEMENT
QUANTUM INFORMATION
QUBITS
RANDOMNESS
STOCHASTIC PROCESSES
TRIPLETS