Creating dynamic symmetry in quantum systems

Amazing stuff!

"“What is very impressive is that they can show that they have this incredible control over the quantum system,” ...

Critically, the researchers observed that the dynamically symmetry of the Hamiltonian — the harmonics of the system’s energy level — dictated which transitions could occur between one state and another. “And the novelty of this work,” Wang says, “is also that we introduce a tool that can be used to characterize any quantum information platform, not just nitrogen-vacancy centers in diamonds. It’s broadly applicable.” Li notes that their technique is simpler than previous methods, those that require constant laser pulses to drive and measure the system’s periodic movement. ..."

From the abstract:

"Periodically driven (Floquet) quantum systems ... Here, we show how to reveal dynamical symmetries, namely, parity, rotation, and particle-hole symmetries, by observing symmetry-induced Floquet selection rules. Notably, we exploit modulated driving to reach the strong light-matter coupling regime, and we introduce a protocol to experimentally extract the transition matrix elements between Floquet states from the system coherent evolution. By using nitrogen-vacancy centers in diamond as an experimental test bed, we execute our protocol to observe symmetry-protected dark states and dark bands, and coherent destruction of tunneling. ..."

Creating dynamic symmetry in quantum systems | MIT News | Massachusetts Institute of Technology MIT researchers develop a new way to control and measure energy levels in a diamond crystal; could improve qubits in quantum computers.

Observation of Symmetry-Protected Selection Rules in Periodically Driven Quantum Systems (no public access)

Observation of symmetry-protected selection rules in periodically driven quantum systems (preprint, open access)