{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,28]],"date-time":"2026-06-28T00:17:40Z","timestamp":1782605860075,"version":"3.54.5"},"reference-count":27,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2013,10,9]],"date-time":"2013-10-09T00:00:00Z","timestamp":1381276800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>Maxwell\u2019s Demon conspires to use information about the state of a confined molecule in a Szilard engine (randomly frozen into a state subspace by his own actions) to derive work from a single-temperature heat bath. It is widely accepted that, if the Demon can achieve this at all, he can do so without violating the Second Law only because of a counterbalancing price that must be paid to erase information when the Demon\u2019s memory is reset at the end of his operating cycle. In this paper, Maxwell\u2019s Demon is analyzed within a \u201creferential\u201d approach to physical information that defines and quantifies the Demon\u2019s information via correlations between the joint physical state of the confined molecule and that of the Demon\u2019s memory. On this view, which received early emphasis in Fahn\u2019s 1996 classical analysis of Maxwell\u2019s Demon, information is erased not during the memory reset step of the Demon\u2019s cycle, but rather during the expansion step, when these correlations are destroyed. Dissipation and work extraction are analyzed here for a Demon that operates a generalized quantum mechanical Szilard engine embedded in a globally closed composite, which also includes a work reservoir, a heat bath and the remainder of the Demon\u2019s environment. Memory-engine correlations lost during the expansion step, which enable extraction of work from the Demon via operations conditioned on the memory contents, are shown to be dissipative when this decorrelation is achieved unconditionally so no work can be extracted. Fahn\u2019s essential conclusions are upheld in generalized form, and his quantitative results supported via appropriate specialization to the Demon of his classical analysis, all without external appeal to classical thermodynamics, the Second Law, phase space conservation arguments or Landauer\u2019s Principle.<\/jats:p>","DOI":"10.3390\/e15104243","type":"journal-article","created":{"date-parts":[[2013,10,9]],"date-time":"2013-10-09T11:57:49Z","timestamp":1381319869000},"page":"4243-4265","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Conditioning, Correlation and Entropy Generation in Maxwell\u2019s Demon"],"prefix":"10.3390","volume":"15","author":[{"given":"Neal","family":"Anderson","sequence":"first","affiliation":[{"name":"Department of Electrical and Computer Engineering, University of Massachusetts Amherst, Amherst, MA 01003-9292, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2013,10,9]]},"reference":[{"key":"ref_1","unstructured":"Maxwell, J.C. 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