Low-temperature coherence properties of Z_2 quantum memory

Abstract

We investigate low-temperature coherence properties of the Z_2 quantum memory which is capable of storing the information of a single logical qubit. We show that the memory has superposition of macroscopically distinct states for some values of a control parameter and at sufficiently low temperature, and that the code states of this memory have no instability except for the inevitable one. However, we also see that the coherence power of this memory is limited by space and time. We also briefly discuss the RVB memory, which is an improvement of the Z_2 quantum memory, and the relations of our results to the obscured symmetry breaking in statistical physics.

9 pages, 8 figures; PRA, accepted

References in corpus (4)

• A no-go theorem for a two-dimensional self-correcting quantum memory based on stabilizer codes
• On thermalization in Kitaev's 2D model
• A statistical mechanics view on Kitaev's proposal for quantum memories
• Visualization of superposition of macroscopically distinct states

Cited by in corpus (6)

• Measures of macroscopicity for quantum spin systems
• Scalable quantum memory in the ultrastrong coupling regime
• Strong entanglement causes low gate fidelity in inaccurate one-way quantum computation
• Probing the Possibilities of Ergodicity in the 1D Spin-1/2 XY Chain with Quench Dynamics
• Macroscopic superpositions as quantum ground states
• Vacuum entanglement governs the bosonic character of magnons