Decoherence-free subspaces in BEC interferometry

Guntupalli Gopi Krishna

Dmitry A. Pushin, M. G. Huber, M. Arif +1 more

A decoherence-free subspace (DFS) is an important class of quantum-error-correcting (QEC) codes that have been proposed for fault-tolerant quantum computation. The applications of QEC techniques, however, are not limited to quantum-information processing (QIP). Here we demonstrate how QEC codes may be used to improve experimental designs of quantum devices to achieve noise suppression. In particular, neutron interferometry is used as a test bed to show the potential for adding quantum error correction to quantum measurements. We built a five-blade neutron interferometer that incorporates both a standard Mach-Zender configuration and a configuration based on a DFS. Experiments verify that the DFS interferometer is protected against low-frequency mechanical vibrations. We anticipate these improvements will increase the range of applications for matter-wave interferometry.

Paolo Facchi A, Angelo Mariano, Saverio Pascazio

Alireza Shabani, Daniel A. Lidar

We introduce a generalized theory of decoherence-free subspaces and subsystems (DFSs), which do not require accurate initialization. We derive a set of conditions for the existence of DFSs within this generalized framework. By relaxing the initialization requirement we show that a DFS can tolerate arbitrarily large preparation errors. This has potentially significant implications for experiments involving DFSs, in particular for the experimental implementation, over DFSs, of the large class of quantum algorithms which can function with arbitrary input states.

Yunkai Wang, Yujie Zhang, Virginia O. Lorenz

We connect the reference frame problem in astronomical interferometry to the concept of decoherence-free subspaces in quantum information. Inspired by this connection, a new scheme that does not rely on reference frame is proposed.

Raisa I. Karasik, Karl-Peter Marzlin, Barry C. Sanders +1 more