How much entanglement can be created in a closed system

Article

关键词: QUANTUM;    ENTROPY;    THERMALIZATION;    COMMUNICATION;    INFORMATION;   

DOI  :  10.1103/PhysRevB.101.060401

来源: SCIE

【 摘 要 】

In a closed system, the total number of particles is fixed. We ask how much does this conservation law restricts the amount of entanglement that can be created. We derive a tight upper bound on the bipartite entanglement entropy in closed systems, and find what a maximally entangled state looks like in such a system. Finally, we illustrate numerically on an isolated system of one-dimensional fermionic gas, that the upper bound can be reached during its unitary evolution, when starting in a pure state that emulates a thermal state with high enough temperature. These results are in accordance with current experiments measuring Renyi-2 entanglement entropy, all of which employ a particle-conserving Hamiltonian, where our bound acts as a loose bound, and will become especially important for bounding the amount of entanglement that can be spontaneously created, once a direct measurement of entanglement entropy becomes feasible.

【 授权许可】

Free