{"id":75,"date":"2022-08-02T15:39:31","date_gmt":"2022-08-02T15:39:31","guid":{"rendered":"http:\/\/localhost:8080\/wordpress\/?page_id=75"},"modified":"2022-08-05T09:01:33","modified_gmt":"2022-08-05T09:01:33","slug":"quantum-heat-engine","status":"publish","type":"page","link":"http:\/\/localhost:8080\/wordpress\/quantum-heat-engine\/","title":{"rendered":"Quantum Heat Engine"},"content":{"rendered":"\n<p class=\"has-medium-font-size\">Understanding the dynamics of heat transport in mesoscopic systems is a topic of great significance in many emergent quantum technologies; such as in superconducting qubits for quantum information studies, and calorimetry for quantum sensing applications.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">To investigate this, we are developing a hybrid-device where we can look at the flow of heat across a superconducting qubit, between two mesoscopic thermal reservoirs. This has been given the popular name of a \u2018<strong>Quantum Heat Engine<\/strong>\u2018, with the energy level spacing of the qubit&nbsp;<em>expanding<\/em>&nbsp;and&nbsp;<em>contracting,&nbsp;<\/em>and transporting heat&nbsp;between the two reservoirs, on a single quanta excitation basis.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">To date, we have developed technology in the laboratory for superconducting qubit studies, based upon the prevalent transmon qubit design, as shown in the figure below, and reported&nbsp;<a href=\"https:\/\/arxiv.org\/abs\/1609.07057\">here<\/a>.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter\"><img src=\"https:\/\/pico.aalto.fi\/old2\/wp-content\/uploads\/ProposalFig.001.jpg\" alt=\"\" class=\"wp-image-2866\"\/><\/figure><\/div>\n\n\n<p><br>Figure 1<\/p>\n\n\n\n<p class=\"has-medium-font-size\">In parallel to this, PICO group has established itself as a leading research group for low temperature thermometry, and we use this expertise to generate and measure heat flow across our devices, using Normal Metal \u2013 Insulator -Superconductor (NIS) heterostructure based bolometry.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">Is it our aim to use this quantum heat engine to further our understanding of heat transport in the quantum limit, and provide a platform for quantum thermodynamic experiments, such as those reported&nbsp;<a href=\"http:\/\/iopscience.iop.org\/article\/10.1088\/1367-2630\/17\/3\/035012\">here&nbsp;<\/a>.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">Such a quantum heat engine can be based on a superconducting qubit coupled to two LC-resonators each including a resistor acting as a reservoir (Fig. 2).<br><a href=\"https:\/\/journals.aps.org\/prb\/abstract\/10.1103\/PhysRevB.94.184503\">Here<\/a>\u00a0we find various operation regimes: nearly adiabatic (low driving frequency), ideal Otto cycle (intermediate frequency), and importantly non-adiabatic coherent regime (high frequency). In the non-adiabatic regime we observe theoretically strong coherent oscillations of the cooling power as a function of frequency as shown in Fig. 3. Our goal is to realize such a quantum refrigerator experimentally, with our first \u2018static\u2019 demonstration reported in\u00a0<a href=\"https:\/\/arxiv.org\/abs\/1801.09312\">arXiv:1801.09312<\/a>.<\/p>\n\n\n\n<p><\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter\"><img src=\"https:\/\/pico.aalto.fi\/old2\/wp-content\/uploads\/QHE.jpg\" alt=\"\" class=\"wp-image-2866\"\/><\/figure><\/div>\n\n\n<p><br>Figure 2<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter\"><img src=\"https:\/\/pico.aalto.fi\/old2\/wp-content\/uploads\/ocsillations.jpg\" alt=\"\" class=\"wp-image-2866\"\/><\/figure><\/div>\n\n\n<p><br>Figure 3<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Understanding the dynamics of heat transport in mesoscopic systems is a topic of great significance in many emergent quantum technologies; such as in superconducting qubits for quantum information studies, and calorimetry for quantum sensing applications. To investigate this, we are developing a hybrid-device where we can look at the flow of heat across a superconducting &hellip; <\/p>\n<p class=\"link-more\"><a href=\"http:\/\/localhost:8080\/wordpress\/quantum-heat-engine\/\" class=\"more-link\">Read more<span class=\"screen-reader-text\"> &#8220;Quantum Heat Engine&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"http:\/\/localhost:8080\/wordpress\/wp-json\/wp\/v2\/pages\/75"}],"collection":[{"href":"http:\/\/localhost:8080\/wordpress\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/localhost:8080\/wordpress\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/localhost:8080\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/localhost:8080\/wordpress\/wp-json\/wp\/v2\/comments?post=75"}],"version-history":[{"count":2,"href":"http:\/\/localhost:8080\/wordpress\/wp-json\/wp\/v2\/pages\/75\/revisions"}],"predecessor-version":[{"id":138,"href":"http:\/\/localhost:8080\/wordpress\/wp-json\/wp\/v2\/pages\/75\/revisions\/138"}],"wp:attachment":[{"href":"http:\/\/localhost:8080\/wordpress\/wp-json\/wp\/v2\/media?parent=75"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}