05.20.+c Quantum information & quantum chaos

Universal quantum computation in integrable systems

Date: 
2016-03-04
Author(s): 

5. S. Lloyd, S. Montangero

Reference: 

arXiv:1407.6634

Quantized integrable systems can be made to perform universal quantum computation by the application of a global time-varying control. The action-angle variables of the integrable system function as qubits or qudits, which can be coupled selectively by the global control to induce universal quantum logic gates. By contrast, chaotic quantum systems, even if controllable, do not generically allow quantum computation under global control.

Absence of Thermalization in Nonintegrable Systems

Date: 
2011-01-24
Author(s): 

Christian Gogolin, Markus P. Müller, and Jens Eisert

Reference: 

Phys. Rev. Lett. 106, 040401 (2011)

We establish a link between unitary relaxation dynamics after a quench in closed many-body systems and the entanglement in the energy eigenbasis. We find that even if reduced states equilibrate, they can have memory on the initial conditions even in certain models that are far from integrable. We show that in such situations the equilibrium states are still described by a maximum entropy or generalized Gibbs ensemble, regardless of whether a model is integrable or not, thereby contributing to a recent debate.

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