Engineering robust and scalable molecular qubits

Symmetry is a crucial element in fundamental physics and is found in everything from particles to crystals. There can be a lack of symmetry in a system.

The barest interference in a qubit system is enough for it to lose any quantum information it may have carried. It makes sense that qubits are most stable in a symmetric environment. The opposite is true for a particular type of qubit.

Researchers from the University of Chicago'sPME, the University of Glasgow, and the Massachusetts Institute of Technology have found that the stability of qubits can be improved by asymmetric environments.

In August, the work was published.

David Awschalom is the Liew Family Professor in Molecular Engineering and Physics at the University of Chicago and the director of the Chicago Quantum Exchange. The method of stabilizing them opens new doors for potential applications.

A classical computer has two quantum states that correspond to one and the other. If disturbed, quantum states will Collapse. The limits of how long a qubit can hold a quantum state are being pushed by physicists.

One way to increase coherence time is to shield qubits from as much external influence as possible, and by placing the qubits in an asymmetric crystal array, the team found that certain quantum states were less sensitive to external magnetic fields.

The asymmetric environment provides "coherence protection" that could allow the qubits to keep their quantum information even in more chaotic places, according to Dan Laorenza, a chemistry graduate student at MIT.

He said that they now understand how to improve coherence of qubits in noisy environments. It's easy to translate this asymmetric environment to many other molecular systems, especially for molecules put in environments like those found in biology.

Maintaining the coherence of qubit sensors is a difficult challenge because they are known for being noisy and unstructured. Better sensors could be found in these research fields if we learned why asymmetric environments are stable against magnetic fields.

More information: S. L. Bayliss et al, Enhancing Spin Coherence in Optically Addressable Molecular Qubits through Host-Matrix Control, Physical Review X (2022). DOI: 10.1103/PhysRevX.12.031028 Journal information: Physical Review X