January 02 2017

Visit by Christian Arenz (Princeton University)

Christian Arenz, a former member of our group and now PostDoc at Princeton University, will visit us on Friday 06.01.2017. He will give a talk at 12 am in room 4.18 on 'Universal control induced by noise'.


Typically the interaction of a quantum system with its environment is considered to be detrimental for quantum information processing. Quantum features one wants to use for quantum information tasks are washed out quickly so that the implementation of quantum gates becomes noisy. In recent decades, however, it has been observed that the environment can also have a beneficial effect. Rather than fighting against the environment, dissipative state preparation and dissipative quantum computing are valuable alternatives to unitary gate designs.
Here we show that the environment can be used as a resource to increase the set of operation that can be implemented with a set of controls. Instead of decreasing the fidelity for implementing a unitary operation, on the basis of the quantum Zeno effect we show that a strong noise process exhibiting a decoherence free subspace can raise the fidelity. The action of the strong dissipation allows the implementation of gate operations that cannot be realized without the help of the dissipation and even full control can be achieved. We discuss our findings on several examples and study how the process fidelity scales with the noise strength.

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