{"id":825514,"date":"2022-03-14T06:00:00","date_gmt":"2022-03-14T13:00:00","guid":{"rendered":"https:\/\/www.microsoft.com\/en-us\/research\/?p=825514"},"modified":"2022-08-17T09:52:54","modified_gmt":"2022-08-17T16:52:54","slug":"microsoft-has-demonstrated-the-underlying-physics-required-to-create-a-new-kind-of-qubit","status":"publish","type":"post","link":"https:\/\/www.microsoft.com\/en-us\/research\/blog\/microsoft-has-demonstrated-the-underlying-physics-required-to-create-a-new-kind-of-qubit\/","title":{"rendered":"Microsoft has demonstrated the underlying physics required to create a new kind of qubit"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-1024x576.jpg\" alt=\"Photo of a quantum computer close-up\" class=\"wp-image-825721\" srcset=\"https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-1024x576.jpg 1024w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-300x169.jpg 300w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-768x432.jpg 768w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-1066x600.jpg 1066w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-655x368.jpg 655w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-343x193.jpg 343w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-240x135.jpg 240w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-640x360.jpg 640w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-960x540.jpg 960w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-1280x720.jpg 1280w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788.jpg 1400w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p><em>Quantum computing promises to help us solve some of humanity\u2019s greatest challenges. Yet as an industry, we are still in the early days of discovering what\u2019s possible. Today\u2019s quantum computers are enabling researchers to do interesting work. However, these researchers often find themselves limited by the inadequate scale of these systems and are eager to do more. Today\u2019s quantum computers are based on a variety of qubit types, but none so far have been able to scale to enough qubits to fully realize the promise of quantum.<\/em><\/p>\n\n\n\n<p><em>Microsoft is taking a more challenging, but ultimately more promising approach to scaled quantum computing with topological qubits that are theorized to be inherently more stable than qubits produced with existing methods without sacrificing size or speed. We have discovered that we can produce the topological superconducting phase and its concomitant Majorana zero modes, clearing a significant hurdle toward building a scaled quantum machine. The explanation of our work and methods below shows that the underlying physics behind a topological qubit are sound\u2014the observation of a 30 \u03bceV topological gap is a first in this work, and one that lays groundwork for the potential future of topological quantum computing. While engineering challenges remain, this discovery proves out a fundamental building block for our approach to a scaled quantum computer and puts Microsoft on the path to deliver a quantum machine in Azure that will help solve some of the world\u2019s toughest problems.<\/em><\/p>\n\n\n\n<p><em>Dr. Chetan Nayak and Dr. Sankar Das Sarma recently sat down to discuss these results and why they matter in the video below.<\/em> L<em>earn more about <a class=\"msr-external-link glyph-append glyph-append-open-in-new-tab glyph-append-xsmall\" href=\"https:\/\/aka.ms\/AAfh3as\" target=\"_blank\" rel=\"noreferrer noopener\">our journey<span class=\"sr-only\"> (opens in new tab)<\/span><\/a> and visit <a class=\"msr-external-link glyph-append glyph-append-open-in-new-tab glyph-append-xsmall\" href=\"https:\/\/azure.microsoft.com\/en-us\/solutions\/quantum-computing\/#quantum-impact\" target=\"_blank\" rel=\"noreferrer noopener\">Azure Quantum<span class=\"sr-only\"> (opens in new tab)<\/span><\/a> to <a class=\"msr-external-link glyph-append glyph-append-open-in-new-tab glyph-append-xsmall\" href=\"https:\/\/cloudblogs.microsoft.com\/quantum\/2022\/03\/21\/explore-azure-quantums-diverse-and-growing-hardware-portfolio-for-free\/\" target=\"_blank\" rel=\"noreferrer noopener\">explore the Azure Quantum hardware profolio<span class=\"sr-only\"> (opens in new tab)<\/span><\/a> and get started with quantum computing today.<\/em><\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"A discussion with Sankar Das Sarma and Chetan Nayak\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube-nocookie.com\/embed\/Q8CHms4ixYc?feature=oembed&rel=0\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><figcaption>Dr. Sankar Das Sarma, a Distinguished University Professor of Physics at University of Maryland joins Dr. Chetan Nayak, Distinguished Engineer of Quantum at Microsoft to discuss Microsoft\u2019s unique approach to building a fully scalable quantum machine.<\/figcaption><\/figure>\n\n\n\n<h2 id=\"microsoft-quantum-team-reports-observation-of-a-30-%ce%bcev-topological-gap-in-indium-arsenide-aluminum-heterostructures\">Microsoft Quantum team reports observation of a 30 <em>\u03bc<\/em>eV topological gap in indium arsenide-aluminum heterostructures<\/h2>\n\n\n\n<p>Topological quantum computation is a route to hardware-level fault tolerance, potentially enabling a quantum computing system with high fidelity qubits, fast gate operations, and a single module architecture. The fidelity, speed, and size of a topological qubit is controlled by a characteristic energy called the topological gap. This path is only open if one can reliably produce a topological phase of matter and experimentally verify that the sub-components of a qubit are in a topological phase (and ready for quantum information processing). Doing so is not trivial because topological phases are characterized by the long-ranged entanglement of their ground states, which is not readily accessible to conventional experimental probes.<\/p>\n\n\n\n<p>This difficulty was addressed by the \u201c<a href=\"https:\/\/www.microsoft.com\/en-us\/research\/publication\/protocol-to-identify-a-topological-superconducting-phase-in-a-three-terminal-device\/\">topological gap protocol<\/a>\u201d (TGP), which our team set forth a year ago as a criterion for identifying the topological phase with quantum transport measurements. Topological superconducting wires have Majorana zero modes at their ends. There is a real fermionic operator localized at each end of the wire, analogous to the real fermionic wave equation constructed by Ettore Majorana in 1937.<\/p>\n\n\n\n\t<div class=\"border-bottom border-top border-gray-300 mt-5 mb-5 msr-promo text-center text-md-left alignwide\" data-bi-aN=\"promo\" data-bi-id=\"1061244\">\n\t\t\n\n\t\n\t<div class=\"row pt-3 pb-4 align-items-center\">\n\t\t\t\t\t\t<div class=\"msr-promo__media col-12 col-md-5\">\n\t\t\t\t<a class=\"bg-gray-300\" href=\"https:\/\/www.microsoft.com\/en-us\/research\/about-microsoft-research\/\" aria-label=\"About Microsoft Research\" data-bi-cN=\"About Microsoft Research\" target=\"_blank\">\n\t\t\t\t\t<img decoding=\"async\" class=\"w-100 display-block\" src=\"https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2024\/07\/About-page-promo_1066x600.jpg\" alt=\"\" \/>\n\t\t\t\t<\/a>\n\t\t\t<\/div>\n\t\t\t\n\t\t\t<div class=\"msr-promo__content p-3 px-5 col-12 col-md\">\n\n\t\t\t\t\t\t\t\t\t<h2 class=\"h4\">About Microsoft Research<\/h2>\n\t\t\t\t\n\t\t\t\t\t\t\t\t<p class=\"large\">Advancing science and technology to benefit humanity<\/p>\n\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"wp-block-buttons justify-content-center justify-content-md-start\">\n\t\t\t\t\t<div class=\"wp-block-button\">\n\t\t\t\t\t\t<a href=\"https:\/\/www.microsoft.com\/en-us\/research\/about-microsoft-research\/\" class=\"btn btn-brand glyph-append glyph-append-chevron-right\" aria-label=\"View our story\" data-bi-cN=\"About Microsoft Research\" target=\"_blank\">\n\t\t\t\t\t\t\tView our story\t\t\t\t\t\t<\/a>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div><!--\/.msr-promo__content-->\n\t<\/div><!--\/.msr-promo__inner-wrap-->\n\t<\/div><!--\/.msr-promo-->\n\t\n\n\n<p>Consequently, there are two quantum states of opposite fermion parity that can only be measured through a phase-coherent probe coupled to both ends. In electrical measurements, the Majorana zero modes (see Figure 1) cause zero-bias peaks (ZBPs) in the local conductance. However, local Andreev bound states and disorder can also cause zero-bias peaks. Thus, the TGP focuses on ZBPs that are highly stable and, crucially, uses the non-local conductance to detect a bulk phase transition. Such a transition must be present at the boundary between the trivial superconducting phase and the topological phase because these are two distinct phases of matter, as different as water and ice.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"867\" src=\"https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_Topo-phase_03-2022-1024x867.png\" alt=\"Quantum computing: Topo phase\" class=\"wp-image-825724\" srcset=\"https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_Topo-phase_03-2022-1024x867.png 1024w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_Topo-phase_03-2022-300x254.png 300w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_Topo-phase_03-2022-768x650.png 768w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_Topo-phase_03-2022-213x180.png 213w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_Topo-phase_03-2022.png 1100w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption>Figure 1: The local density of states of a topological superconducting nanowire as a function of energy and position.<\/figcaption><\/figure>\n\n\n\n<p>We have simulated our devices using models that incorporate the details of the materials stack, geometry, and imperfections. Our simulations have demonstrated that the TGP is a very stringent criterion, rendering it a reliable method for detecting the topological phase in a device. Crucially, the conditions for passing the protocol\u2014the presence of stable ZBPs at both ends of the device over a gapped region with gapless boundary, as established via the non-local conductance\u2014were established before any devices had been measured. Given the subtleties involved in identifying a topological phase, which stem from the absence of a local order parameter, one of the design principles of the TGP was to avoid confirmation bias. In particular, the device is scanned over its entire operating range instead of \u2018hunting\u2019 for a specific desired feature, such as a ZBP.<\/p>\n\n\n\n<p>Microsoft\u2019s Station Q, in Santa Barbara, CA, is the birthplace of Microsoft\u2019s quantum program. For the last 16 years, it has been the host of a biannual conference on topological phases and quantum computing. After a two-year hiatus of in-person meetings due to the pandemic, the Station Q meetings resumed in early March. At this meeting with leaders in quantum computing from across industry and academia, we reported that we have multiple devices that have passed the TGP.<\/p>\n\n\n\n<p>Our team has measured topological gaps exceeding 30 <em>\u03bc<\/em>eV. This is more than triple the noise level in the experiment and larger than the temperature by a similar factor. This shows that it is a robust feature. This is both a landmark scientific advance and a crucial step on the journey to topological quantum computation, which relies on the fusion and braiding of anyons (the two primitive operations on topological quasiparticles). The topological gap controls the fault-tolerance that the underlying state of matter affords to these operations. More complex devices enabling these operations require multiple topological wire segments and rely on TGP as part of their initialization procedure. Our success was predicated on very close collaboration between our simulation, growth, fabrication, measurement, and data analysis teams. Every device design was simulated in order to optimize it over 23 different parameters prior to fabrication. This enabled us to determine the device tuning procedure during design.<\/p>\n\n\n\n<p>Our results are backed by exhaustive measurements and rigorous data validation procedures. We obtained the large-scale phase diagram of multiple devices, derived from a combination of local and non-local conductances. Our analysis procedure was validated on simulated data in which we attempted to fool the TGP. This enabled us to rule out various null hypotheses with high confidence. Moreover, data analysis was led by a different team than the one who took the data, as part of our checks and balances between different groups within the team. Additionally, an expert council of independent consultants is vetting our results, and the response to date is overwhelmingly positive.<\/p>\n\n\n\n<p>With the underlying physics demonstrated, the next step is a topological qubit. We hypothesize that the topological qubit will have a favorable combination of speed, size, and stability compared to other qubits. We believe ultimately it will power a fully scalable quantum machine in the future, which will in turn enable us to realize the full promise of quantum to solve the most complex and pressing challenges our society faces.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Quantum computing promises to help us solve some of humanity\u2019s greatest challenges. Yet as an industry, we are still in the early days of discovering what\u2019s possible. Today\u2019s quantum computers are enabling researchers to do interesting work. However, these researchers often find themselves limited by the inadequate scale of these systems and are eager to [&hellip;]<\/p>\n","protected":false},"author":40306,"featured_media":825721,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"msr-url-field":"","msr-podcast-episode":"","msrModifiedDate":"","msrModifiedDateEnabled":false,"ep_exclude_from_search":false,"footnotes":""},"categories":[1],"tags":[],"research-area":[243138],"msr-region":[],"msr-event-type":[],"msr-locale":[268875],"msr-post-option":[],"msr-impact-theme":[],"msr-promo-type":[],"msr-podcast-series":[],"class_list":["post-825514","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research-blog","msr-research-area-quantum","msr-locale-en_us"],"msr_event_details":{"start":"","end":"","location":""},"podcast_url":"","podcast_episode":"","msr_research_lab":[],"msr_impact_theme":[],"related-publications":[],"related-downloads":[],"related-videos":[],"related-academic-programs":[],"related-groups":[],"related-projects":[],"related-events":[],"related-researchers":[{"type":"user_nicename","value":"Dr. Chetan Nayak","user_id":31457,"display_name":"Dr. Chetan Nayak","author_link":"<a href=\"https:\/\/www.microsoft.com\/en-us\/research\/people\/cnayak\/\" aria-label=\"Visit the profile page for Dr. Chetan Nayak\">Dr. Chetan Nayak<\/a>","is_active":false,"last_first":"Nayak, Dr. Chetan","people_section":0,"alias":"cnayak"}],"msr_type":"Post","featured_image_thumbnail":"<img width=\"960\" height=\"540\" src=\"https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-960x540.jpg\" class=\"img-object-cover\" alt=\"Photo of a quantum computer close-up\" decoding=\"async\" loading=\"lazy\" srcset=\"https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-960x540.jpg 960w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-300x169.jpg 300w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-1024x576.jpg 1024w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-768x432.jpg 768w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-1066x600.jpg 1066w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-655x368.jpg 655w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-343x193.jpg 343w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-240x135.jpg 240w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-640x360.jpg 640w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788-1280x720.jpg 1280w, https:\/\/www.microsoft.com\/en-us\/research\/uploads\/prod\/2022\/03\/Quantum-blog_ChetanNayak_03-2022_1400x788.jpg 1400w\" sizes=\"(max-width: 960px) 100vw, 960px\" \/>","byline":"<a href=\"https:\/\/www.microsoft.com\/en-us\/research\/people\/cnayak\/\" title=\"Go to researcher profile for Dr. Chetan Nayak\" aria-label=\"Go to researcher profile for Dr. Chetan Nayak\" data-bi-type=\"byline author\" data-bi-cN=\"Dr. Chetan Nayak\">Dr. Chetan Nayak<\/a>","formattedDate":"March 14, 2022","formattedExcerpt":"Quantum computing promises to help us solve some of humanity\u2019s greatest challenges. Yet as an industry, we are still in the early days of discovering what\u2019s possible. Today\u2019s quantum computers are enabling researchers to do interesting work. However, these researchers often find themselves limited by&hellip;","locale":{"slug":"en_us","name":"English","native":"","english":"English"},"_links":{"self":[{"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/posts\/825514"}],"collection":[{"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/users\/40306"}],"replies":[{"embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/comments?post=825514"}],"version-history":[{"count":17,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/posts\/825514\/revisions"}],"predecessor-version":[{"id":870627,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/posts\/825514\/revisions\/870627"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/media\/825721"}],"wp:attachment":[{"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/media?parent=825514"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/categories?post=825514"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/tags?post=825514"},{"taxonomy":"msr-research-area","embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/research-area?post=825514"},{"taxonomy":"msr-region","embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/msr-region?post=825514"},{"taxonomy":"msr-event-type","embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/msr-event-type?post=825514"},{"taxonomy":"msr-locale","embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/msr-locale?post=825514"},{"taxonomy":"msr-post-option","embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/msr-post-option?post=825514"},{"taxonomy":"msr-impact-theme","embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/msr-impact-theme?post=825514"},{"taxonomy":"msr-promo-type","embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/msr-promo-type?post=825514"},{"taxonomy":"msr-podcast-series","embeddable":true,"href":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/wp\/v2\/msr-podcast-series?post=825514"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}