Generating entanglement rapidly and reliably is essential for quantum information processing, communication, and metrology. Dissipative preparation is attractive because engineered reservoirs robustly drive a system toward an entangled target, yet relaxation can carry a substantial time cost. Here we formulate the entanglement Mpemba effect, whereby an initially less entangled state overtakes a more entangled state under the same open-system dynamics. This effect turns initial-state engineering into a route for faster preparation without altering the dissipative protocol. We derive a general criterion for the reversal from the relaxation spectrum, applicable even when entanglement evolves nonmonotonically. A reversal of deterministic local operations and classical communication (LOCC)-reachability preorder provides a measure-independent certificate of reversed entanglement order. Exactly solvable models show that initial-state selection can substantially shorten the time required to reach high entanglement. We further propose an experimentally relevant trapped-ion protocol that can realize the entanglement Mpemba effect.
Extreme first-passage events are broadly relevant to biological, chemical, and physical processes in which the first successful arrival determines the outcome. Existing theories are confined to noninteracting searchers. Interacting extreme-statistics problems are notoriously difficult because correlations destroy probability factorization. We establish a general framework for interacting extreme search. A no-go theorem shows that broad classes of bounded interactions cannot beat the $1/\ln N$ extreme timescale of $N$ independent Brownian searchers, and complementary upper bounds prove that this scale is exact for broad classes of repulsive interactions. We then identify two sharp mechanisms beyond the logarithmic class and derive a unified interaction-driven acceleration limit. In particular, deterministic pairwise interaction can at most reduce the extreme search time to order $1/N$, while stochastic pairwise forcing attains $1/(N\ln N)$. Our results separate acceleration due to statistical redundancy from that generated by coherent many-body transport or amplified fluctuations, deepening our understanding of interacting stochastic systems.
We solve exactly a finite-time thermodynamic optimal control problem for two nonreciprocally interacting Brownian particles translated by two harmonic traps. The controller manipulates both the center and separation of the pair. Nonreciprocal interactions generate an internal active force that couples these two channels. The optimal protocol is oscillatory, deliberately opens the dimer even when the target separation is unchanged, and can extract work during transport. A central finding is a finite critical time beyond which the external-work infimum is $-\infty$: at any prescribed duration beyond this threshold, both extractable work and output power are unbounded. Physical regularizations such as finite trap range and force saturation restore a finite optimum and convert the anomaly into optimal-protocol transitions: in the zero-target case, a hard finite range produces a first-order-like jump from the zero protocol to a maximum-range protocol, whereas smooth force saturation gives a continuous, second-order-like onset. Under finite-range constraints, the optimal protocol can further undergo multiple finite-time transitions, producing multiple work-duration kinks with no qualitative analog in prior studies.
Ruicheng Bao· 0 citations
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