Quantum computation, quantum state engineering, and quantum phase transitions driven by dissipation

TL;DR

This paper demonstrates that dissipative quantum systems can be used for universal quantum computation, state preparation, and exhibit novel phase transitions, with potential for experimental verification using current technology.

Contribution

It introduces a model where steady states of dissipative systems enable universal quantum computation and state engineering, highlighting robustness and new phase transition phenomena.

Findings

Dissipative systems can perform universal quantum computation.

Steady states can encode complex quantum states like topological order.

Dissipative phase transitions are experimentally verifiable.

Abstract

We investigate the computational power of creating steady-states of quantum dissipative systems whose evolution is governed by time-independent and local couplings to a memoryless environment. We show that such a model allows for efficient universal quantum computation with the result of the computation encoded in the steady state. Due to the purely dissipative nature of the process, this way of doing quantum computation exhibits some inherent robustness and defies some of the DiVincenzo criteria for quantum computation. We show that there is a natural class of problems that can be solved with such a model - the preparation of ground states of frustration free quantum Hamiltonians. This allows for robust and efficient creation of exotic states that exhibit features like topological quantum order and the creation of PEPS and it proves the existence of novel dissipative phase transitions. In particular the latter can in principle be verified experimentally with present day technology such as with optical lattices.