From geometric twists to high-temperature quantum coherence
A geometric twist in a strongly-interacting insulator can lead to strong zero modes.
Quantum coherence is a key ingredient for qubits, but evading the loss of this coherence is a challenge. For qubits emerging in many-particle systems, quantum coherence can be lost even due to the dynamics of the microscopic constituents and suppressing this requires "cold" matter: where the role of all but the lowest-energy states can be neglected.
This study shows how geometrical twists in certain strongly-interacting insulators can open a path to an entirely different approach: one where high-energy states themselves become qubits, thus dramatically expanding the possible settings for quantum coherence.
The geometrical twists in the quasi-one-dimensional systems considered in this work are not unlike the one familiar from the iconic shape of DNA or the twists found in other well-known systems such as carbon nanotubes. In the present context, such twists are shown to lead to forms of interactions conducive to the emergence of so-called strong zero modes, a recently proposed paradigm for elevating high-energy states, and thereby "hot" matter, into the domain of quantum coherence. The strong zero modes in this work turn out to have parafermionic origin, even though they arise in an ordinary fermionic system. The systems proposed in this study offer insights towards creating such zero modes and observing high-temperature quantum coherence in experiments.
Strong Zero Modes from Geometric Chirality in Quasi-One-Dimensional Mott Insulators, R. A. Santos and B. Béri, Phys. Rev. Lett. 125, 207201 (2020).