Quantum thermodynamics and thermal quantum information transfer

F.G.A. van den Berg

Thermal Relational Quantum Thermodynamics

Jincheng Zhang

This paper proposes a novel approach to quantum information transfer, termed "Quantum Entanglement Entropy Transfer (EET)." The core claim is that by precisely controlling the micro-scale entropy transfer between entangled particles, direct quantum information transmission can be achieved without relying on physical media, circumventing the limitations imposed by classical communication bottlenecks. The proposed mechanism utilizes non-classical thermodynamics and a specifically designed "entropy pump" system. This system leverages microscopic thermal fluctuations within entangled particles to facilitate non-local entropy transfer, thereby driving changes in the entanglement correlation between the particles. Mathematical formalism is presented to describe the entropy transfer process, highlighting the role of entanglement entropy and the thermodynamic parameters governing the system. The novelty of this approach lies in its utilization of entanglement as the primary medium for entropy transfer, coupled with the practical demands of quantum information transmission. The theoretical framework presented offers a potentially transformative pathway for quantum communication, moving beyond conventional approaches and opening avenues for ultra-fast, secure information transfer.

Sebastian Deffner, Steve Campbell

Piotr Ćwikliński, Michał Studziński

Coherences between different energy levels are strongly constrained by thermodynamics. Here we ask whether several coherence transfers that can be optimized separately can also be optimized simultaneously by the same thermodynamic process. Using an energy-resolved Stinespring representation of thermal operations, we express elementary transfer amplitudes as inner products of bath-weighted vectors. Joint saturation imposes collinearity and phase-closure conditions on these vectors, which must all arise from one energy-preserving system--bath unitary. This gives necessary compatibility conditions for arbitrary finite-dimensional Hamiltonians. We show that joint incompatibility persists in a system with both degenerate and nondegenerate energy levels: rigorous computer-assisted semidefinite-program bounds, combined with explicit thermal constructions, prove that three individual thermal optima cannot be approached simultaneously. We then determine how well different coherences can be protected when their optima are incompatible. For a four-level family at infinite temperature, we obtain the complete closed retention region and the cost of balancing the coherences relative to their individual optima. At positive temperature, covariance and Gibbs preservation permit joint retention that no thermal operation can approach. Finite-bath constructions and certified semidefinite relaxations bound the balanced thermal performance. When two coherences carry independent phases, these bounds describe simultaneous preservation of interference visibility and phase Fisher information.

Jincheng Zhang

This paper introduces the concept of Quantum Correlation Heat Capacity (QCHC), denoted as C_corr, as an independent thermodynamic response function characterizing the temperature-dependent evolution of quantum correlations within multipartite systems. While traditional thermodynamics defines heat capacity solely through the lens of internal energy variations with respect to temperature, namely C = (partial E) / (partial T), the framework presented here posits that information-theoretic measures—specifically quantum mutual information I(A:B)—exhibit their own distinct thermal storage and transfer dynamics. We define the quantum correlation heat capacity as C_corr = T * (partial I(A:B)) / (partial T), capturing the rate at which quantum correlation energy or informational configuration changes per unit temperature shift. By bridging quantum information theory and statistical mechanics, we demonstrate that temperature variations can induce an independent correlation heat storage capacity that operates orthogonally to ordinary energetic degrees of freedom. This formulation expands the conventional set of thermodynamic state variables, offering profound implications for quantum thermodynamics, information erasure, and the foundations of statistical mechanics.

Austin K. Daniel, Yuri V. Rostovtsev