Conductor of Heat Death: The Charge Palette of a Quantum Bath ✦

Original: "Tuning the Quantum Mpemba Effect in Isolated System by Initial State Engineering"

· Yihan Yu, Tianren Jin, Lv Zhang, Kai Xu, Heng Fan

arXiv:2505.02040v2 · 2025-05-04 · CC BY · ⏱ 1 min · Quantum Physics

By varying the charge spread in a thermal reservoir, physicists have learned to make quantum systems forget their past at different rates.

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By varying the charge spread in the thermal environment, one can speed up or slow down the relaxation of a quantum system — like a conductor controlling the tempo of fading music. Imagine a choir: voices scattered across octaves — the soloist dissolves instantly; in unison — sounds longer. So it is here: the width of the bath's charge spectrum sets the speed of quantum forgetting. In perspective — quantum processors, where qubit lifetimes are tuned not by shielding, but by a symphony of symmetries. Irreversibility becomes not a verdict, but an instrument.

🎯 The classical Mpemba effect was noted as early as Aristotle, and rediscovered by Tanzanian schoolboy Erasto Mpemba in 1963 while making ice cream.

🎬 The ability to conduct the pace of thermalization echoes the concept of 'entropy slowdown' from Greg Egan's novel 'Permutation City'.

S = k_B \ln \Omega

Entropy is proportional to the logarithm of the number of accessible microstates; a dense bath spectrum means rapid entropy growth and, as a result, acceleration of relaxation.

\Delta S_A = \mathrm{tr}\left[ \rho ( \log\rho - \log\rho_Q ) \right]

Quantum-information measure of deviation from equilibrium; ρ is the subsystem's density matrix, ρ_Q is its fully charge-symmetrized version. The faster this quantity decreases, the sooner the system thermalizes.

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Conductor of Heat Death: The Charge Palette of a Quantum Bath ✦