Nanowelding of quantum spin-12 chains at minimal dissipation

Author(s)

Cavalcante, Moallison F. ; Bonanca, Marcus V. S. ; Miranda, Eduardo ; Deffner, Sebastian

• Document type: Journal article
• Source: PHYSICAL REVIEW B; v. 110, n. 6, p. 12-pg., 2024-08-05.

Abstract

We consider the optimal control of switching on a coupling term between two quantum many-body systems. Specifically, we (i) quantify the energetic cost of establishing a weak junction between two quantum spin-1/2 chains in finite time r and (ii) identify the energetically optimal protocol to realize it. For linear driving protocols, we find that for long times the excess (irreversible) work scales as tau(-n), where n = 1, 2 or a nonuniversal number depending on the phase of the chains. Interestingly, increasing a J(z) anisotropy in the chains suppresses the excess work, thus promoting quasiadiabaticity. The general optimal control problem is solved, employing a Chebyshev Ansatz. We find that the optimal control protocol is intimately sensitive to the chain phases. (AU)

• FAPESP's process: 22/15453-0 - Correlated quantum materials
• Grantee: Eduardo Miranda
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 20/02170-4 - Optimal thermodynamic processes in out-of-equilibrium systems
• Grantee: Marcus Vinicius Segantini Bonança
• Support Opportunities: Regular Research Grants