We conducted a comprehensive numerical simulation study on the practical limitations of information engines (energy harvesters) based on Maxwell's Demon, as well as on the quantum information thermodynamic breakthroughs that overcome these limitations. First, using a rigorous master equation simulation (Partial-Secular Semilocal Lindblad approach) of an autonomous engine employing quantum dots, we identified its fatal vulnerabilities (breakdown thresholds) to heat leakage and measurement errors. Furthermore, as a scalable architecture to overcome these limitations, we proposed an "Information Conveyor Belt based on continuous measurement and Bayesian inference" using superconducting circuits, and demonstrated powerful work extraction against a massive reverse bias in a 10-dot chain. Finally, challenging the prohibition of perpetual motion machines dictated by the classical Landauer's principle (information erasure cost), we proved the phenomenon of "negative erasure cost (Quantum Landauer Loophole)" using maximum quantum entanglement via simulations, thereby demonstrating the physical feasibility of true second-kind perpetual motion operation (pure power generation by spontaneous thermal excitation) at room temperature.
We conducted a comprehensive numerical simulation study on the practical limitations of information engines (energy harvesters) based on Maxwell's Demon, as well as on the quantum information thermodynamic breakthroughs that overcome these limitations. First, using a rigorous master equation simulation (Partial-Secular Semilocal Lindblad approach) of an autonomous engine employing quantum dots, we identified its fatal vulnerabilities (breakdown thresholds) to heat leakage and measurement errors. Furthermore, as a scalable architecture to overcome these limitations, we proposed an "Information Conveyor Belt based on continuous measurement and Bayesian inference" using superconducting circuits, and demonstrated powerful work extraction against a massive reverse bias in a 10-dot chain. Finally, challenging the prohibition of perpetual motion machines dictated by the classical Landauer's principle (information erasure cost), we proved the phenomenon of "negative erasure cost (Quantum Landauer Loophole)" using maximum quantum entanglement via simulations, thereby demonstrating the physical feasibility of true second-kind perpetual motion operation (pure power generation by spontaneous thermal excitation) at room temperature.
We present a unified theoretical, numerical, and experimental investigation into autonomous information heatengines (Maxwell’s demons), bridging microscopic open quantum thermodynamics, stochastic continuous moni-toring, deep reinforcement learning, and practical energy harvesting engineering. First, addressing widespreadnumerical pitfalls in quantum thermodynamics simulations, we identify an operator sign inversion in detailed-balance jump rates that previously simulated an unphysical “perpetual motion machine” yielding −19.29 kB T .Once corrected via adaptive Runge-Kutta integration, we prove that single-step work extraction from maximallyentangled Bell states is strictly bounded by kB T ln 2, and that the cyclic entropy accounting of entanglement re-generation imposes a net non-negative work cost (Wnet ≥ 0), establishing quantum entanglement as a consumedthermodynamic fuel rather than a violation of the Second Law. Second, using positive-preserving Rouchon-Ralphstochastic master equation mappings across 48 trajectory ensembles, we evaluate an Information Conveyor Beltin a 10-dot chain under continuous homodyne detection. We demonstrate that while an isolated cryogenic demonreservoir (TM = 4.2 K) enables positive extracted power, incorporating the mandatory Carnot refrigeration over-head required to maintain the cryostat exactly cancels all efficiency advantages, yielding an overall system deficitmatching the isothermal baseline. Third, we address autonomous control in partially observable Markov deci-sion processes (POMDPs) by deploying Recurrent Proximal Policy Optimization (Recurrent PPO with LSTM),enabling the demon to autonomously overcome measurement backaction and discover synchronized conveyor trans-port policies superior to classical heuristics. Finally, we design and verify Configuration D, a body-heat-poweredthermoelectric energy harvester operating an ESP32-C3 microcontroller demon. By eliminating idle wake-timedelays and overlapping 9-bit digital sensor conversion with sub-millisecond USB polling, firmware v2 slashes ac-tive controller consumption in our calibrated design model by a factor of 8.7 (from ≈ 208.5 mJ to ≈ 24.1 mJ),establishing a net-positive self-powered operational cycle (+65.8 mJ/cycle). We quantify the fundamental gap of≈ 8.4 × 1018 (≈ 19 orders of magnitude) between the Landauer erasure limit (2.87 × 10−21 J) and real-worldmicrocontrollers, delineating the rigorous boundary between physical information thermodynamics and real-worldenergy harvesting.
Abstract Whether quantum computational speedups translate to fundamental thermodynamic energy savings remains unresolved. We establish the first rigorous connection between computational complexity and thermodynamic costs through DEMON(I,E) complexity classes that classify information-processing protocols by information complexity I(n) and erasure energy E(n). Four theorems prove: (1) any g-bit erasure dissipates >= g X k_B T ln 2, generalizing Landauer's principle; (2) measurement disturbance D reduces extractable work to (I-D)k_B T ln 2; (3) Grover-based quantum demons achieve provably optimal Theta(sqrt{N}) thermodynamic advantage over classical search, tight by the BBBV lower bound; and (4) quantum walks on d-dimensional lattices exhibit a dense hierarchy with continuous scaling exponent (d-1)/(2d). Computational validation across six orders of magnitude confirms predictions with <1% error. Experimental predictions include 20.5X energy reduction for trapped-ion Grover search (N=1024, T=1 mK) and 11X effective cooling for superconducting circuit QED heat-bath protocols. This work unifies 158 years of Maxwell demon research, connects algorithmic complexity to physical energy costs, and enables experimental verification of quantum thermodynamic advantages beyond computational speedup.
Standard stochastic heat engines operate blindly, enforcing work extraction protocols indiscriminately on microstates, and consequently suppressing work output, stability, efficiency. To overcome this, we propose an Otto information engine (OIE) that employs a Maxwell's demon to filter out detrimental stochastic trajectories, and demonstrate that the OIE can provide enhanced work output and stability compared to the corresponding standard Otto engine. Remarkably, even after accounting for the energetic costs of the demon, the OIE efficiency surpasses both the standard Otto limit and Carnot bound. Furthermore, by applying the fluctuation theorem of information dissipation, we derive upper and lower bounds on efficiency, confirming that our results adhere to the second law of thermodynamics. Finally, and counterintuitively, measurement errors and quantum inner friction, traditionally considered deleterious, can be harnessed as resources, which improves robustness and enables us to ignore the adiabatic strokes time.
We analyze an engine whose working fluid consists of a single quantum particle, paralleling Szilard's construction of a classical single-particle engine. Following his resolution of Maxwell's Second Law paradox using the latter, which turned on physically instantiating the demon (control subsystem), the quantum engine's design mirrors the classically-chaotic Szilard Map that operates a thermodynamic cycle of measurement, thermal-energy extraction, and memory reset. Focusing on the thermodynamic costs to observe and control the particle and comparing these in the quantum and classical limits, we detail the thermodynamic tradeoffs behind Landauer's Principle for information-processing-induced thermodynamic dissipation in the quantum and classical regimes. In particular, and as found with the classical engine, we show that the sum of the thermodynamic costs over a cycle obeys a generalized Landauer Principle, exactly balancing energy extraction from the heat bath. Thus, the quantum engine obeys the Second Law. However, the quantum engine does so via substantially different mechanisms: classically measurement and erasure determine the thermodynamics, while in the quantum implementation the cost of partition insertion is key.
This work provides an overview of key historical developments in the formulation of the Second Law of Thermodynamics, focusing on the notorious challenge of ``Maxwell's Demon'', a hypothetical creature who could presumably violate that law. It begins by recalling Maxwell's challenge and discussing the apparent loophole in the Second Law that appears to make such a violation possible. An alternative formulation of the Demon challenge by Szilard is considered, along with his attempted defeat of the Demon through reference to measurement. A similar effort by Brillouin is also analyzed. The proposal of Bennett to defeat the Demon through the requirement of memory erasure is critically discussed. Finally, it is proposed that the Second Law gains a firm foundation through neglected features of quantum theory. In particular, an application of the Heisenberg Uncertainty Principle is shown to decisively defeat the Demon, as well as to serve as justification for Landauer's Principle, albeit in terms distinct from the usual computational formulation.
In scenarios coined Maxwell's demon, information on microscopic degrees of freedom is used to seemingly violate the second law of thermodynamics. This has been studied in the classical as well as the quantum domain. In this paper, we study an implementation of Maxwell's demon that can operate in both domains. In particular, we investigate information-to-work conversion over the quantum-to-classical transition. The demon continuously measures the charge state of a double quantum dot and uses this information to guide electrons against a voltage bias by tuning the on-site energies of the dots. Coherent tunneling between the dots allows for the buildup of quantum coherence in the system. Under strong measurements, the coherence is suppressed, and the system is well-described by a classical model. As the measurement strength is further increased, the Zeno effect prohibits interdot tunneling. A Zeno-like effect is also observed for weak measurements, where measurement errors lead to fluctuations in the on-site energies, dephasing the system. We anticipate similar behaviors in other quantum systems under continuous measurement and feedback control, making our results relevant for implementations in quantum technology and quantum control. Published by the American Physical Society 2024