Quantum Many-Body Scars and Weak Ergodicity Breaking in Rydberg-Atom Quantum Simulators

A perennial mystery of nature is how order can exist amidst chaos. Familiar systems such as the clock pendulum exhibit regular periodic motion. This ordered behaviour, however, is fragile. For example, interactions between particles rapidly lead to chaos, forcing the system to thermalise and forget its initial state. This can be visualised as an ice cream that melts away and never finds its way back to the frozen state. Quantum scars refer to the surprising behaviour that defies such common intuition: for special initial states, the ice cream periodically melts away and then freezes up again. Recent experiments on ultracold Rydberg atoms have found evidence of similar behaviour where the atoms were able to return to their initial state many times during the measurement. At this point, the origins of quantum many-body scars largely remain a mystery. Your project will develop computer simulations of quantum many-body scars in systems of ultra cold atoms in optical lattices, with the goal of predicting future experiments on these systems that may unlock a range of applications in the emerging quantum technologies.

<p>Recent state-of-the-art experiments on a quantum simulator built from strongly-correlated Rydberg atoms [H. Bernien et al., Nature 551, 579 (2017)] have discovered a remarkable dynamical phenomenon that challenged the conventional notion of how quantum systems reach thermal equilibrium. We have recently proposed the first theoretical explanation for this phenomenon and named it &quot;quantum many-body scars&quot; [Nature Physics 14, 745 (2018]. Following the surge of international interest in this topic, including popular articles such as&nbsp;&nbsp;<a href="https://www.quantamagazine.org/quantum-scarring-appears-to-defy-universes-push-for-disorder-20190320/">https://www.quantamagazine.org/quantum-scarring-appears-to-defy-universes-push-for-disorder-20190320/</a>, this project will contribute to the on-going quest to understand the mathematical origins of quantum many-body scars and their unusual dynamical properties. The practical benefits of this research will be new computational techniques for simulating non-ergodic many-body dynamics and phases of matter, and their potential use as a platform for robust quantum technology that could operate at arbitrarily high temperatures.&nbsp;&nbsp;</p> <p>The initial phase of the project will focus on: (i) learning about quantum dynamics, thermalisation, and related phenomena (integrability, many-body localisation), and (ii) learning how to numerically simulate quantum many-body systems (e.g., using Python, C++, or any preferred language). In particular, you will learn how to apply quantum information concepts to characterise dynamics and thermalisation (e.g., entanglement entropy and spectrum). You will apply all these tools to investigate in the detail the toy model of a 1D Rydberg atom chain, then extend the known results by investigating various physical perturbations to the model.</p> <p>Desired student background:&nbsp;We seek talented and highly-motivated physics students to pursue this project in the general area of quantum many-body physics, which intersects with the fields of quantum information and condensed matter physics. A significant component of the project is numerical modelling of quantum many-body systems via exact diagonalisation and related techniques (e.g., matrix product states, DMRG, etc.), thus the project is particularly suitable for those with strong interest in computational physics and numerical simulations.</p> <p>For an accessible introduction to quantum many-body scars, see our recent review article: <a href="https://arxiv.org/abs/2011.09486">https://arxiv.org/abs/2011.09486</a></p>

<p>Formal applications for research degree study should be made online through the&nbsp;<a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University&#39;s website</a>. Please state clearly in the Planned Course of Study that you are applying for <em><strong>PHD Physics &amp; Astronomy FT</strong></em> and&nbsp;in the research information section&nbsp;that the research degree you wish to be considered for is <em><strong>Quantum Many-Body Scars and Weak Ergodicity Breaking in Rydberg-Atom Quantum Simulators</strong></em>&nbsp;as well as&nbsp;<a href="mailto:https://eps.leeds.ac.uk/physics/staff/4124/dr-zlatko-papic">Dr Zlatko Papic</a> as your proposed supervisor&nbsp;and in the finance section, please state clearly&nbsp;<em><strong>the funding that you are applying for, if you are self-funding or externally sponsored</strong></em>.</p> <p>If English is not your first language, you must provide evidence that you meet the University&#39;s minimum English language requirements (below).</p> <p style="text-align:start; margin-bottom:24px"><em><strong>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</strong></em></p> <p>Applications will be considered on an ongoing basis. &nbsp;Potential applicants are strongly encouraged to contact the supervisors for an informal discussion before making a formal application. &nbsp;We also advise that you apply at the earliest opportunity as the application and selection process may close early, should we receive a sufficient number of applications or that a suitable candidate is appointed.</p> <p>Please note that you must provide the following documents in support of your application&nbsp;by the closing date of 3 April 2024 for Leeds Opportunity Research Scholarship, 8 April 2024 for Leeds Doctoral Scholarship/&nbsp;or 28 June 2024 if not applying for these scholarships:&nbsp;</p> <ul> <li>Full Transcripts of all degree study or if in final year of study, full transcripts to date</li> <li>Personal Statement outlining your interest in the project</li> <li>CV</li> </ul>

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid.

<p><strong>Self-Funded or externally sponsored students are welcome to apply.</strong></p> <p><strong>UK</strong>&nbsp;&ndash;&nbsp;The&nbsp;<a href="https://phd.leeds.ac.uk/funding/209-leeds-doctoral-scholarships-2022">Leeds Doctoral Scholarships</a>&nbsp;and&nbsp;<a href="https://phd.leeds.ac.uk/funding/234-leeds-opportunity-research-scholarship-2022">Leeds Opportunity Research Scholarship</a>&nbsp;are available to UK applicants. The&nbsp;<a href="https://phd.leeds.ac.uk/funding/102-bell-burnell-scholarship-award-awarded-by-the-iop">Bell Burnell Scholarship Award</a>&nbsp;is available to support applicants who are from groups that are currently under-represented in physics (awarded by the IOP &ndash;&nbsp;now closed for 2024/25 entry).&nbsp;&nbsp;<a href="https://phd.leeds.ac.uk/funding/60-alumni-bursary">Alumni Bursary</a>&nbsp;is available to graduates of the University of Leeds.</p> <p><strong>Non-UK</strong>&nbsp;&ndash;&nbsp;The&nbsp;<a href="https://phd.leeds.ac.uk/funding/48-china-scholarship-council-university-of-leeds-scholarships-2021">China Scholarship Council - University of Leeds Scholarship</a>&nbsp;is available to nationals of China (now closed for 2024/25 entry. The&nbsp;<a href="https://phd.leeds.ac.uk/funding/73-leeds-marshall-scholarship">Leeds Marshall Scholarship</a>&nbsp;is available to support US citizens.&nbsp;<a href="https://phd.leeds.ac.uk/funding/60-alumni-bursary">Alumni Bursary</a>&nbsp;is available to graduates of the University of Leeds.</p> <p><strong>Important:</strong>&nbsp; Any costs associated with your arrival at the University of Leeds to start your PhD including flights, immigration health surcharge/medical insurance and Visa costs are&nbsp;<strong>not</strong>&nbsp;covered under these studentships.</p> <p>Please refer to the&nbsp;<a href="https://www.ukcisa.org.uk/">UKCISA</a>&nbsp;website for information regarding Fee Status for Non-UK Nationals.</p>

<p>For further information about your application, please contact Doctoral College Admissions by email to&nbsp;<a href="mailto:maps.pgr.admissions@leeds.ac.uk">maps.pgr.admissions@leeds.ac.uk</a></p> <p>For further information about this project, please contact Dr Zlatko Papic by email to&nbsp;<a href="mailto:Z.Papic@leeds.ac.uk">Z.Papic@leeds.ac.uk</a></p>