The chiral qubit: quantum computing with chiral anomaly

The quantum chiral anomaly enables a nearly non-dissipative current in the presence of chirality imbalance. We propose to utilize the chiral anomaly for the designs of qubits potentially capable of operating at THz frequency and at room temperature with a coherence time to gate time ratio of about 10⁴. The proposed “Chiral Qubit” is a micron-scale ring made of a Weyl or Dirac semimetal, with the |0〉 and |1〉 states corresponding to the symmetric and antisymmetric superpositions of chiral currents circulating along the ring clockwise and counter-clockwise. A fractional magnetic flux through the ring induces a quantum superposition of the |0〉 and |1〉quantum states. The entanglement of qubits can be implemented through the near-field THz frequency electromagnetic fields (EMF). We show that the Hamiltonian of the chiral qubit is similar to that of the superconducting qubit. This means that quantum gates can be implemented in a traditional way, and the algorithms developed for superconducting quantum processors will apply. Light-driven (THz) ultrafast topology switching, demonstrated experimentally in Dirac/Weyl semimetal recently, will be discussed.

The author is grateful for collaborations with Dmitri Kharzeev and Jigang Wang.