September 2023 - Qse-grad-students

[cancel to be rescheduled] Re: [QMatter in Math/Physics 2023 Sept 29th Fri 10 am - 11:30 am ET] Soonwon Choi (MIT) Exact Quantum Algorithms to Recognize Phases of Matter and Exactly Solvable 2D Models with Anomalous Bipartite and Topological Entanglement Entropy - Harvard CMSA G10

by Juven Wang

Apology: The talk will be rescheduled due to the speaker Soonwon informing us that he became sick. We hope that Soonwon will recover soon! On Mon, Sep 25, 2023 at 10:13 PM Juven Wang <jw(a)cmsa.fas.harvard.edu> wrote: > Please circulate! > > Let us welcome Prof. Soonwon Choi, in Live Action! > > Quantum Matter in Mathematics and Physics (QMMP) 2023: > https://cmsa.fas.harvard.edu/event_category/quantum-matter-seminar/ > > ----- > This seminar will be in person! > *Time: Sept 29th Fri 10 am - 11:30 am ET * > > *Location: Harvard CMSA G10* > Zoom: https://harvard.zoom.us/j/977347126 > Password: cmsa > ————————————————————————————————— > > Soonwon Choi (MIT) > > Title: > Exact Quantum Algorithms to Recognize Phases of Matter and > Exactly Solvable 2D Models with Anomalous Bipartite and Topological > Entanglement Entropy > > Abstract: > In this talk, I will report my two recent results at the intersection of > quantum information and strongly interacting phases of matters. > > In the first half of the talk, we describe exact quantum algorithms that > recognize a class of 1D gapped phases, namely symmetry protected > topological phases or spontaneous symmetry breaking phases protected by > abelian internal symmetry. The key idea is to observe the conceptual > similarity between renormalization group (RG) flow and error correction, > and to implement the latter as unitary circuits emulating the RG flow. Our > algorithm guarantees faithful recognition of a target phase with a small > number of input quantum state samples. > > In the second half, we present a class of 2D Hamiltonians, where the exact > ground state wavefunctions can be exactly evaluated and shown to exhibit > anomalous entanglement properties. One class of our models exhibit area-law > scaling entanglement entropy, but this is mostly due to non-local > correlation: one finds that the topological entanglement entropy also > scales with the size of subsystem choices. By making simple modifications, > we can also devise 2D models with volume-law scaling bipartite entanglement > entropy. Our results can be understood as a generation of the 1D Motzkin > model to 2D systems. > > Based on: > Work done with Ethan Lake and Shankar Balasubramanian > https://arxiv.org/abs/2211.09803 > https://arxiv.org/abs/2305.07028 > > > --- > Harvard University CMSA, > 20 Garden Street, > Cambridge, MA 02138 >

7 months, 1 week

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[QMatter in Math/Physics 2023 Sept 28th Thur 4:30 pm - 6:00 pm ET] Cenke Xu (UCSB) Quantum field theory approach to quantum information - Harvard CMSA G10

by Juven Wang

Please circulate! Let us welcome Prof. Cenke Xu, in Live Action! Quantum Matter in Mathematics and Physics (QMMP) 2023: https://cmsa.fas.harvard.edu/event_category/quantum-matter-seminar/ ----- This seminar will be in person! *Time: Sept 28, Thur 4:30 pm - 6:00 pm ET * *Location: Harvard CMSA G10* Zoom: https://harvard.zoom.us/j/977347126 Password: cmsa ————————————————————————————————— Cenke Xu (UCSB) Title: Quantum field theory approach to quantum information Abstract: We apply the formalism of quantum field theory and Euclidean space-time path integral to investigate a class of quantum information problems. In particular, we investigate quantum many-body systems under weak-measurement and decoherence. The Euclidean space-time path integral allows us to map this problem to a quantum field theory with (temporal) boundary or defects. We therefore investigate two types of quantum many-body systems with nontrivial boundary physics: quantum critical points, and states with nontrivial topology, such as Chern insulator and symmetry protected topological states. For example, we demonstrate that a Wilson-Fisher quantum critical point can be driven into an "extraordinary-log" phase after weak-measurement. Another example is that, we argue that a system with higher form symmetry may be driven to a self-dual phase transition under weak-measurement. --- Harvard University CMSA, 20 Garden Street, Cambridge, MA 02138

7 months, 1 week

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[QMatter in Math/Physics 2023 Sept 29th Fri 10 am - 11:30 am ET] Soonwon Choi (MIT) Exact Quantum Algorithms to Recognize Phases of Matter and Exactly Solvable 2D Models with Anomalous Bipartite and Topological Entanglement Entropy - Harvard CMSA G10

by Juven Wang

Please circulate! Let us welcome Prof. Soonwon Choi, in Live Action! Quantum Matter in Mathematics and Physics (QMMP) 2023: https://cmsa.fas.harvard.edu/event_category/quantum-matter-seminar/ ----- This seminar will be in person! *Time: Sept 29th Fri 10 am - 11:30 am ET * *Location: Harvard CMSA G10* Zoom: https://harvard.zoom.us/j/977347126 Password: cmsa ————————————————————————————————— Soonwon Choi (MIT) Title: Exact Quantum Algorithms to Recognize Phases of Matter and Exactly Solvable 2D Models with Anomalous Bipartite and Topological Entanglement Entropy Abstract: In this talk, I will report my two recent results at the intersection of quantum information and strongly interacting phases of matters. In the first half of the talk, we describe exact quantum algorithms that recognize a class of 1D gapped phases, namely symmetry protected topological phases or spontaneous symmetry breaking phases protected by abelian internal symmetry. The key idea is to observe the conceptual similarity between renormalization group (RG) flow and error correction, and to implement the latter as unitary circuits emulating the RG flow. Our algorithm guarantees faithful recognition of a target phase with a small number of input quantum state samples. In the second half, we present a class of 2D Hamiltonians, where the exact ground state wavefunctions can be exactly evaluated and shown to exhibit anomalous entanglement properties. One class of our models exhibit area-law scaling entanglement entropy, but this is mostly due to non-local correlation: one finds that the topological entanglement entropy also scales with the size of subsystem choices. By making simple modifications, we can also devise 2D models with volume-law scaling bipartite entanglement entropy. Our results can be understood as a generation of the 1D Motzkin model to 2D systems. Based on: Work done with Ethan Lake and Shankar Balasubramanian https://arxiv.org/abs/2211.09803 https://arxiv.org/abs/2305.07028 --- Harvard University CMSA, 20 Garden Street, Cambridge, MA 02138

7 months, 2 weeks

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Re: [QMatter in Math/Physics 2023 Sept 22 Fri 10:00 - 11:30 am ET] Margarita Davydova (MIT) Floquet codes, automorphisms, and quantum computation- Harvard CMSA G10

by Juven

Friendly reminder - On Sept 22, Friday 10:00 am - 11:30 am ET. Let us welcome Margarita. On Fri, Sep 15, 2023 at 8:00 PM Juven <jw(a)cmsa.fas.harvard.edu> wrote: > Please circulate! > > Quantum Matter in Mathematics and Physics (QMMP) 2023: > https://cmsa.fas.harvard.edu/event_category/quantum-matter-seminar/ > > ----- > This seminar will be in person! > *Time: Sept 22, Friday 10:00 am - 11:30 am ET * > > *Location: Harvard CMSA G10* > Zoom: https://harvard.zoom.us/j/977347126 > Password: cmsa > ————————————————————————————————— > > Margarita Davydova (MIT) > > *Title: Floquet codes, automorphisms, and quantum computation* > > *Abstract:* > > In this talk, I will introduce a new kind of measurement-based quantum > computation inspired by Floquet codes. In this model, the quantum logical > gates are implemented by short sequences of low-weight measurements which > simultaneously encode logical information and enable error correction. We > introduce a new class of quantum error-correcting codes generalizing > Floquet codes that achieve this, which we call dynamic automorphism > (DA) codes. > > As in Floquet codes, the instantaneous codespace of a DA code at any fixed > point in time is that of a topological code. In this case, the quantum > computation can be viewed as a sequence of time-like domain walls > implementing automorphisms of the topological order, which can be > understood in terms of reversible anyon condensation paths in a particular > parent model. This talk will introduce all of these concepts as well as > provide a new perspective for thinking about Floquet codes. > > The explicit examples that we construct, which we call DA color codes, can > implement the full Clifford group of logical gates in 2+1d by two- and, > rarely three-body measurements. Using adaptive two-body measurements, we > can achieve a non-Clifford gate in 3+1d, making the first step towards > universal quantum computation in this model. > > The talk is based on recent work with Nathanan Tantivasadakarn, Shankar > Balasubramanian, and David Aasen [arxiv: 2307.10353]. > > ————————————————————————————————— > Subscribe to Harvard CMSA Quantum Matter and other seminar videos > (more to be uploaded): > https://www.youtube.com/playlist?list=PL0NRmB0fnLJQAnYwkpt9PN2PBKx4rvdup > > Subscribe to Harvard CMSA seminar mailing list: > https://forms.gle/1ewa7KeP6BxBuBeRA >

7 months, 2 weeks

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TODAY: Special Quantum Computing Seminar -- Peter Zoller and Christian Kokail

by Cotler, Jordan Saul

Dear all, We are excited to have Peter Zoller and Christian Kokail for the second Special Quantum Computing seminar today at Jefferson Hall 250. The talk will start at 3:30 pm. Title - Exploring Large-Scale Entanglement in Quantum Simulation Abstract - Entanglement is a distinguishing feature of quantum many-body systems, and uncovering the entanglement structure for large particle numbers in quantum simulation experiments is a fundamental challenge in quantum information science. Here we perform experimental investigations of entanglement based on the entanglement Hamiltonian, as an effective description of the reduced density operator for large subsystems. We prepare ground and excited states of a 1D XXZ Heisenberg chain on a 51-ion programmable quantum simulator and perform sample-efficient `learning' of the entanglement Hamiltonian for subsystems of up to 20 lattice sites. Our experiments provide compelling evidence for a local structure of the entanglement Hamiltonian. This observation marks the first instance of confirming the fundamental predictions of quantum field theory by Bisognano and Wichmann, adapted to lattice models that represent correlated quantum matter. The reduced state takes the form of a Gibbs ensemble, with a spatially-varying temperature profile as a signature of entanglement. Our results also show the transition from area to volume-law scaling of Von Neumann entanglement entropies from ground to excited states. As we venture towards achieving quantum advantage, we anticipate that our findings and methods have wide-ranging applicability to revealing and understanding entanglement in many-body problems with local interactions including higher spatial dimensions. Hope to see you all there. Sincerely, Jordan Cotler

7 months, 2 weeks

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Fwd: [MIT iQuISE] Interest Meeting & Kickoff Social at 6PM (9/20) in 36-462

by Ploucha, Clare

Please see the below announcement that may be of interest to the HQI community. ================================================== Hi everyone, tl;dr MIT's interdisciplinary Quantum Information Science and Engineering (iQuISE) society will be hosting an interest meeting and social to kick off the academic year. When: 6PM ET on Sept 20 (Wednesday) Where: Allen Room (MIT Building 36, Room 462) Why: Learn about a great community while eating free pizza! Who: Open to all Harvard/MIT Affiliates (undergrad, MS, MBA, PhD, postdoc, etc.) Please fill out this interest form if you'd like to join us: https://tinyurl.com/<https://urldefense.proofpoint.com/v2/url?u=https-3A__engage.mit.edu_click-3…>iquise<https://urldefense.proofpoint.com/v2/url?u=https-3A__engage.mit.edu_click-3…>2023interest<https://urldefense.proofpoint.com/v2/url?u=https-3A__engage.mit.edu_click-3…> -- the long: MIT iQuISE is MIT's longest-standing quantum computing and engineering community open to all MIT/Harvard affiliates (PhD, MS, undergrad, MBA, etc.). Our initiatives include an invited talk series<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.iquise.mit.edu_-23…> by distinguished pioneers in our field, MIT's quantum computing hackathon (MIT iQuHACK<https://urldefense.proofpoint.com/v2/url?u=https-3A__iquhack.mit.edu_&d=DwM…>), MIT's quantum science and engineering conference (QuARC<https://urldefense.proofpoint.com/v2/url?u=https-3A__cqe.mit.edu_quarc2023_…>), local and global outreach, and other events that bring together the community in quantum engineering and science at MIT. Join our community to shape these initiatives and spearhead your own, while building a powerful professional network in both academia and industry. See you there! Ariel Ariel Barr PhD candidate, Efthimios Kaxiras group @ Harvard Treasurer @ MIT iQuISE<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.iquise.mit.edu_&d=…> [A white and black logo with green text Description automatically generated]

7 months, 2 weeks

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TOMORROW: Special Quantum Computing Seminar -- Peter Zoller and Christian Kokail

by Cotler, Jordan Saul

Dear all, We are excited to have Peter Zoller and Christian Kokail the second Special Quantum Computing seminar on Sept 21 at Jefferson Hall 250. The talk will start at 3:30 pm. Title - Exploring Large-Scale Entanglement in Quantum Simulation Abstract - Entanglement is a distinguishing feature of quantum many-body systems, and uncovering the entanglement structure for large particle numbers in quantum simulation experiments is a fundamental challenge in quantum information science. Here we perform experimental investigations of entanglement based on the entanglement Hamiltonian, as an effective description of the reduced density operator for large subsystems. We prepare ground and excited states of a 1D XXZ Heisenberg chain on a 51-ion programmable quantum simulator and perform sample-efficient `learning' of the entanglement Hamiltonian for subsystems of up to 20 lattice sites. Our experiments provide compelling evidence for a local structure of the entanglement Hamiltonian. This observation marks the first instance of confirming the fundamental predictions of quantum field theory by Bisognano and Wichmann, adapted to lattice models that represent correlated quantum matter. The reduced state takes the form of a Gibbs ensemble, with a spatially-varying temperature profile as a signature of entanglement. Our results also show the transition from area to volume-law scaling of Von Neumann entanglement entropies from ground to excited states. As we venture towards achieving quantum advantage, we anticipate that our findings and methods have wide-ranging applicability to revealing and understanding entanglement in many-body problems with local interactions including higher spatial dimensions. Hope to see you all there. Sincerely, Jordan Cotler

7 months, 2 weeks

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Special Quantum Computing Seminar Sep 14 - Prof. James Whitfield

by Anshu, Anurag

Dear all, We are excited to have Prof. James D. Whitfield (Dartmouth) deliver the first Special Quantum Computing seminar on Sept 14 at Jefferson Hall 250. Refreshments will begin at 3. The talk will start at 3:30, followed by a mentorship session with Prof. Whitfield 4:15 pm - 5 pm (details below). Title - At the intersection of quantum computing and quantum chemistry Abstract - Investment in quantum technology is driven by industrial and commercial potential. Only a few applications are as widely known as the quantum simulation of chemistry. As a result, there have been many interesting questions sparked at the intersection of quantum chemistry and quantum computing. In this talk, I will focus on the key role that the single-particle orbitals play in computing electronic structures both with and without quantum resources. The orbitals dictate the reliability of numerical results, the number of qubits needed to perform quantum simulations, and, in some cases, even the computational complexity of the ground state. I will give two examples of orbital selections that dramatically change the computational complexity of the electronic structure ground problem [1,2]. [1] Intractability of Electronic Structure in a Fixed Basis. Bryan O’Gorman, Sandy Irani, James Whitfield, and Bill Fefferman PRX Quantum 3, 020322 (2022) [2] Basis set generation and optimization in the NISQ era with Quiqbox.jl. Weishi Wang and James Whitfield. arXiv:2212.04586 Mentorship session - Aimed at students and early career researchers, the mentorship session will allow the audience to engage with Prof. Whitfield on questions related to career and research directions. The questions can range anywhere from ''Is research in quantum computing a good career choice?" to "How can I understand density functional theory as a computer scientist?". These important questions usually come up in one-to-one conversations at the end of a seminar, but our goal here will be to openly discuss and benefit from them. Hope to see you all there. With Best Regards, Anurag Anshu

7 months, 3 weeks

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FW: Harvard University Police Department Campus Advisory

by Ploucha, Clare

Hi all, Please read this message from HUPD below. Several people in our community have received these scam emails. Best, Clare -- Clare Ploucha Director of Programs Harvard Quantum Initiative 33 Oxford Street, Maxwell Dworkin 347 Cambridge, MA 02138 From: "Catalano, Steven G." <steven_catalano(a)hupd.harvard.edu> Date: Tuesday, September 5, 2023 at 10:43 PM To: "@Campus Notify (campus-notify-all(a)harvard.edu)" <campus-notify-all(a)harvard.edu> Subject: Harvard University Police Department Campus Advisory Email Scam The Harvard University Police Department wishes to inform our community of an ongoing scam targeting Harvard University affiliates. The scam appears to originate from a Harvard email address and offers recipients free musical instruments, in exchange for paying the delivery costs. The scammer requests interested parties contact them via text and submit payment via an online money transfer service (Zelle, Venmo, CashApp, etc.). The HUPD is actively investigating these incidents and is informing members of our community about these scams in an attempt to prevent future loss of finances or personal information. If you receive this scam email, or a message similar to it, please do not respond. Below please find additional information regarding common scams and possible actions affiliates can take in the event they are contacted by scammers. Important Knowledge Regarding Scams • U.S. Government (IRS, Immigration/Citizenship Services, and Department of State) officials will never ask for prepaid gift cards or debit/credit card information over the telephone. • Law enforcement officials will never request payment in order to resolve a warrant or criminal issue. • Affiliates are cautioned when using informal means to locate housing (Craigslist, Facebook, or Reddit). Affiliates are strongly encouraged to utilize the Off-Campus Housing website in order to locate rental properties. Commons Characteristics of Scams • Caller/sender does not identify themselves or claims association with a government organization/department (IRS, law enforcement, Department of State). • Caller/sender demands affiliate to act quickly. • Caller/sender notifies affiliate of concerning information of which the affiliate was not previously aware (problem with taxes, immigration status, active warrant). • Caller/sender requests payment in cash or by gift card. • Caller/sender prohibits affiliate from notifying other individuals of the situation. Steps to Take If You Receive a Scam Telephone Call/Email • Do not share any personal identifiable or financial information. • Monitor calls/email for potential scams from unknown callers/sender. • If you suspect the caller/sender is attempting to commit a scam, hang up or do not respond. • Do not agree to meet with an unknown caller/sender. If the caller/sender claims to be a government official, you should contact Harvard International Office (HIO), which can work with HUPD as needed to verify the caller/sender’s credentials. • If you feel unsafe or threatened, call the HUPD at 617-495-1212. External Resources for More Information • Federal Trade Commission for Rental Scams - https://www.consumer.ftc.gov/articles/0079-rental-listing-scams<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.consumer.ftc.gov_a…> • Federal Trade Commission Information for Avoiding Scams - https://consumer.ftc.gov/features/avoiding-scams-information-recent-refugee…<https://urldefense.proofpoint.com/v2/url?u=https-3A__consumer.ftc.gov_featu…> • U.S. Citizen and Immigration Services website on Common Scams - https://www.uscis.gov/avoid-scams/common-scams<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.uscis.gov_avoid-2D…> • Federal Trade Commission to Report Identity Theft - https://www.identitytheft.gov/?utm_source=takeaction<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.identitytheft.gov_…> • Harvard International Office (HIO) regarding housing - http://hio.harvard.edu/housing For more detailed information on safety and security, please read the Harvard University Police Department's Annual Security Report, which can be found at www.hupd.harvard.edu/annual-security-report<http://www.hupd.harvard.edu/annual-security-report>. Additionally, please review “Scams and Identity Theft Attempts Targeting International Affiliates”, which can be found at https://www.hupd.harvard.edu/scams-targeting-international-affiliates. For questions about this message, please contact the Harvard University Police Department's Public Information Officer, Steven G. Catalano, at 617-495-9225 or by email at steven_catalano(a)hupd.harvard.edu<mailto:steven_catalano@hupd.harvard.edu>. Under the Clery Act, institutions are required to maintain two types of alert systems for separate and distinct purposes, Emergency Notifications and Timely Warnings. Emergency Notifications are sent via the MessageMe system upon the confirmation of a significant emergency or dangerous situation involving an immediate threat to the health or safety of students, employees, or visitors occurring on the campus. Timely Warnings are sent via email to the University community when a situation occurs within Harvard’s Clery Geography and represents a serious or continuing threat. Beginning in the 2023-2024 academic year, the HUPD will also disseminate Campus Advisories, which cover non-emergency incidents that do not rise to the requirements of Emergency Notifications or Timely Warnings. Disseminated at 4:45 PM on September 5, 2023. Steven G. Catalano Special Advisor to Chief of Police/Public Information Officer Harvard University Police Department 1033 Massachusetts Avenue, 6th floor Cambridge, Massachusetts 02138 617-495-9225 steven_catalano(a)hupd.harvard.edu<mailto:steven_catalano@hupd.harvard.edu>

8 months

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