{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T03:45:45Z","timestamp":1783395945484,"version":"3.54.6"},"reference-count":21,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2021,9,27]],"date-time":"2021-09-27T00:00:00Z","timestamp":1632700800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100005073","name":"Agency for Defense Development","doi-asserted-by":"publisher","award":["Defense-Specialized project"],"award-info":[{"award-number":["Defense-Specialized project"]}],"id":[{"id":"10.13039\/501100005073","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003626","name":"Defense Acquisition Program Administration","doi-asserted-by":"publisher","award":["Defense-Specialized project"],"award-info":[{"award-number":["Defense-Specialized project"]}],"id":[{"id":"10.13039\/501100003626","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>Quantum illumination uses entangled light that consists of signal and idler modes to achieve higher detection rate of a low-reflective object in noisy environments. The best performance of quantum illumination can be achieved by measuring the returned signal mode together with the idler mode. Thus, it is necessary to prepare a quantum memory that can keep the idler mode ideal. To send a signal towards a long-distance target, entangled light in the microwave regime is used. There was a recent demonstration of a microwave quantum memory using microwave cavities coupled with a transmon qubit. We propose an ordering of bosonic operators to efficiently compute the Schrieffer\u2013Wolff transformation generator to analyze the quantum memory. Our proposed method is applicable to a wide class of systems described by bosonic operators whose interaction part represents a definite number of transfer in quanta.<\/jats:p>","DOI":"10.3390\/e23101260","type":"journal-article","created":{"date-parts":[[2021,9,27]],"date-time":"2021-09-27T21:40:30Z","timestamp":1632778830000},"page":"1260","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["A Method to Compute the Schrieffer\u2013Wolff Generator for Analysis of Quantum Memory"],"prefix":"10.3390","volume":"23","author":[{"given":"Dong-Hwan","family":"Kim","sequence":"first","affiliation":[{"name":"Emerging Science and Technology Directorate, Agency for Defense Development, Daejeon 34186, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Su-Yong","family":"Lee","sequence":"additional","affiliation":[{"name":"Emerging Science and Technology Directorate, Agency for Defense Development, Daejeon 34186, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2992-304X","authenticated-orcid":false,"given":"Yonggi","family":"Jo","sequence":"additional","affiliation":[{"name":"Emerging Science and Technology Directorate, Agency for Defense Development, Daejeon 34186, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Duk Y.","family":"Kim","sequence":"additional","affiliation":[{"name":"Emerging Science and Technology Directorate, Agency for Defense Development, Daejeon 34186, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zaeill","family":"Kim","sequence":"additional","affiliation":[{"name":"Emerging Science and Technology Directorate, Agency for Defense Development, Daejeon 34186, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Taek","family":"Jeong","sequence":"additional","affiliation":[{"name":"Emerging Science and Technology Directorate, Agency for Defense Development, Daejeon 34186, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,9,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1038\/nature08812","article-title":"Quantum computers","volume":"464","author":"Ladd","year":"2010","journal-title":"Nature"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1038\/s41586-020-2103-5","article-title":"Experimental demonstration of memory-enhanced quantum communication","volume":"580","author":"Bhaskar","year":"2020","journal-title":"Nature"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1463","DOI":"10.1126\/science.1160627","article-title":"Enhanced Sensitivity of Photodetection via Quantum Illumination","volume":"321","author":"Lloyd","year":"2008","journal-title":"Science"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"253601","DOI":"10.1103\/PhysRevLett.101.253601","article-title":"Quantum Illumination with Gaussian States","volume":"101","author":"Tan","year":"2008","journal-title":"Phys. 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