2025/05/07 by Sukrut Mondkar, Aparajita Bhattacharyya, Mondkar, Sukrut +3 · 2 citations
Computer Science · Physics and Astronomy · #Absorption refrigerator #Advanced Thermodynamics and Statistical Mechanics #Cooling capacity #Hamiltonian (control theory) #Quantum #Quantum Information and Cryptography #Quantum many-body systems #Qubit #Refrigeration #Refrigerator car #Scaling #quant-ph
paper · pdf · doi:10.48550/arxiv.2505.04374
published in arXiv (Cornell University) (Cornell University) · version accepted in PRA
openalex publication_date 2025/05/07 · openalex created_date 2025/10/10 · arxiv created 2026/07/18 · openalex updated_date 2026/08/05 · arxiv updated 2026/08/07
We examine a quantum absorption refrigerator that comprises three qubits, each of which is connected with a separate spin-star environment, with the three qubit-bath units coupled through an effective six-body interaction. The refrigerator exhibits the feature of transient cooling, i.e., lowering of the temperature of the first qubit in sufficiently small timescales, rather than steady-state refrigeration. A key advantage of our model is that the symmetries of the Hamiltonian enable a semi-analytic solution of the reduced density matrices of the refrigerator qubits, even in the presence of a large number of environmental spins. We derive the condition for autonomous refrigeration and analyze how the optimal cold-qubit temperature scales with the number of bath spins. We find a power-law scaling towards a constant asymptotic value. We also find the scaling of the minimum time required for optimal cooling as a function of the number of bath spins. Furthermore, we quantify the non-Markovianity of the cold-qubit dynamics using a restricted Breuer-Laine-Piilo information-backflow measure and observe that stronger backflow correlates with lower transient minimum temperatures across the sampled parameter regime. The transient-cooling performance is found to be robust under broad parameter variations. Compared to a conventional Markovian three-qubit refrigerator, the CSQAR achieves lower cold-qubit temperatures on shorter timescales. We further analyze the heat currents associated with the three qubits and their respective baths.