2024/11/30 by M. V. Fistul, Fistul, M. V., Oliver Neyenhuys +9
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Quantum optics and atomic interactions #Semiconductor Quantum Structures and Devices
paper · pdf · doi:10.48550/arxiv.2412.00391
We study collective quantum phases and quantum phase transitions occurring in frustrated sawtooth arrays of small quantum Josephson junctions. Frustration is introduced through the periodic arrangement of 0- and π- Josephson junctions with the Josephson coupling energies αEJ of different signs, -1≤ α≤ 1. The complexity of the potential landscape of the system is controlled by the frustration parameter f=(1-α)/2. The potential energy has a single global minimum in the non-frustrated regime (ffcr=0.75). We address the coherent quantum regime and identify several collective quantum phases: disordered (insulating) and ordered (superconducting) phases in the non-frustrated regime, as well as highly entangled patterns of vortices and anti-vortices in the frustrated regime. These collective quantum phases are controlled by several physical parameters: the frustration f, the Josephson coupling, and the charging energies of junctions and islands. We map the control parameter phase diagram by characterizing the quantum dynamics of frustrated Josephson junction arrays by spatially and temporally resolved quantum-mechanical correlation function of the local magnetization.