October 2023 - Qse-grad-students

Special Quantum Information Seminar Oct 26 - Prof. Liang Jiang

by Anshu, Anurag

Dear all, We are excited to have Prof. Liang Jiang from University of Chicago deliver our next Special Quantum Information Seminar on Thursday Oct 26. The talk will be 2:45-3:30 pm, followed by a mentorship session with Prof. Jiang 3:30-4:00 pm. Note the timing change from the previous seminar. Title: Co-Designed Quantum Error Correction Abstract: To effectively address practical imperfections while harnessing the power of quantum information processing, our goal is to design quantum error correction schemes that can not only suppress dominant errors specific to particular hardware but also meet the requirements of various applications. I will discuss the process of designing quantum error-correcting codes that can optimally suppress practically relevant errors, with examples of custom-designed quantum error correction schemes that can efficiently correct practically relevant errors in AMO and solid-state platforms. I will also explore quantum error-correcting codes designed for various applications in quantum computing, communication, and sensing. Mentorship session - Aimed at students and early career researchers, the mentorship session will allow the audience to engage with Prof. Jiang 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 help with practical quantum error correction as a theorist?". 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

5 months, 3 weeks

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Quantum Information Seminar by Matthias C. Caro

by Anshu, Anurag

Dear all, We are excited to have Matthias Caro from Freie Universität Berlin give a talk on Nov 2 (Thursday) from 4:30 pm - 5:30 pm in Jefferson 250. Details below and see you all there! Title: Classical Verification of Quantum Learning Abstract: Quantum data access and quantum processing can make certain classically intractable learning tasks feasible. However, quantum capabilities will only be available to a select few in the near future. Thus, reliable schemes that allow classical clients to delegate learning to untrusted quantum servers are required to facilitate widespread access to quantum learning advantages. Building on a recently introduced framework of interactive proof systems for classical machine learning, we develop a framework for classical verification of quantum learning. Based on a new quantum data access model that we call "mixture-of-superpositions" quantum examples, we exhibit learning problems that a classical learner cannot efficiently solve on their own, but that they can efficiently and reliably solve when interacting with an untrusted quantum prover. In contrast, we showcase two general scenarios in learning and verification in which quantum mixture-of-superpositions examples do not lead to sample complexity improvements over classical data. Our results demonstrate that the potential power of quantum data for learning tasks, while not unlimited, can be utilized by classical agents through interaction with untrusted quantum entities. With Best Regards, Anurag Anshu

6 months

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[QMatter in Math/Physics 2023 Nov 3, Fri 10:00 - 11:30 am ET] Meng Cheng (Yale) Symmetry and many-body topology in mixed states - Harvard CMSA G10

by Juven Wang

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: Nov 3rd, Fri 10-11:30 am ET* *Location: Harvard CMSA G10* Zoom: https://harvard.zoom.us/j/977347126 Password: cmsa ————————————————————————————————— Meng Cheng (Yale) Title: Symmetry and many-body topology in mixed states Abstract: It is by now well-understood that gapped ground states of local Hamiltonians can be classified topologically, and the nontrivial states exhibit many interesting topological phenomena. In this talk I’ll discuss recent developments in generalizing the topological classification to mixed states. Global symmetry plays a key role in understanding phases in pure states. For mixed states, certain “weak” symmetries may hold “on average” for the entire ensemble, in contrast to “strong" symmetries respected by each state in the ensemble. I will show that the interplay between these two kinds of symmetries lead to a rich landscape of symmetry-protected mixed states, and can also be used to characterize mixed state topological order. -------- 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

6 months

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[Joint QMatter seminar 2023 Nov 2, Thu 4:30 pm - 6 pm ET] Liujun Zou (Perimeter) Landscape of quantum phases in quantum materials - Harvard CMSA G10

by Juven Wang

Please circulate --- Next seminar will be next Thursday (Nov 2). We skip our seminar this week to avoid the conflict with the ongoing important events: (1) Mathematics in Science: Perspectives and Prospects (10/27-10/28) (2) Kickoff Workshop for the Simons Collaboration on Celestial Holography (10/26-10/29). Joint Seminar of Quantum Matter in Mathematics and Physics (QMMP) and Topological Quantum Matter seminar: https://cmsa.fas.harvard.edu/event_category/quantum-matter-seminar/ https://cmsa.fas.harvard.edu/event_category/topological-quantum-matter-semi… ----- This seminar will be in person! *Time: Nov 2, Thu 4:30 pm - 6 pm ET* *Location: Harvard CMSA G10* Zoom: https://harvard.zoom.us/j/977347126 Password: cmsa ————————————————————————————————— Liujun Zou (Perimeter) Title: Landscape of quantum phases in quantum materials Abstract: A central goal of condensed matter physics is to understand which quantum phases of matter can emerge in a quantum material. For this purpose, one should be able to not only describe the quantum phases using some effective field theories, but also capture the important microscopic information of the material via mathematical formulation. In this talk, I will present a framework to classify quantum phases in quantum materials, where the microscopic information of a material is encoded in its quantum anomaly. I will talk about the application of this framework to classify various exotic quantum phases of matter in different lattice systems. Using our framework, we have obtained many results unexpected from the previous literature. -------- 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 --- Harvard University CMSA, 20 Garden Street, Cambridge, MA 02138

6 months, 1 week

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Wednesday, Nov. 1: HQI Special Seminar – Attosecond Quantum Optics

by Gallagher, Claire M.

HQI Special Seminar – Prof. Ido Kaminer Wednesday, Nov. 1 4:30 PM – 5:30 PM Jefferson 250 Ido Kaminer, Technion Title: "Attosecond Quantum Optics" The role of the quantum features of light in attosecond processes has remained unexplored. In a series of recent works, we developed the quantum-optical theory of attosecond processes and applied it to high harmonic generation (HHG). In this talk, I will show how the correlations between the emitters induce correlations between the emitted harmonics. Furthermore, I will show that the spectrum of HHG is sensitive to the photon statistics of the driving light. Thermal and squeezed light substantially increase the efficiency of HHG compared to a coherent light of the same intensity. The prospects of the attosecond quantum optics include the engineering of quantum many-photon states of light and creation of entangled attosecond pulses. Sincerely, Claire ___________ Claire M. Gallagher Staff Assistant III Harvard Quantum Initiative - MD 351

6 months, 1 week

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[QMatter in Math/Physics 2023 Oct 20, Fri 10:00 - 11:30 am ET] Cheryne Jonay (Stanford) A Physical Theory of Two-stage Thermalization - Harvard CMSA G10

by Juven Wang

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: Oct 20th Fri 10-11:30 am ET* *Location: Harvard CMSA G10* Zoom: https://harvard.zoom.us/j/977347126 Password: cmsa ————————————————————————————————— Cheryne Jonay (Stanford) *A Physical Theory of Two-stage Thermalization* One indication of thermalization time is subsystem entanglement reaching thermal values. Recent studies on local quantum circuits reveal two exponential stages with decay rates $r_1$ and $r_2$ of the purity before and after thermalization. We provide an entanglement membrane theory interpretation, with $r_1$ corresponding to the domain wall free energy. Circuit geometry can lead to $r_1 < r_2$, producing a ``phantom eigenvalue". Competition between the domain wall and magnon leads to $r_2 < r_1$ when the magnon prevails. However, when the domain wall wins, this mechanism provides a practical approach for measuring entanglement growth through local correlation functions. -------- 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 --- Harvard University CMSA, 20 Garden Street, Cambridge, MA 02138

6 months, 2 weeks

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Fwd: CNS Open House - Poster Request

by Ploucha, Clare

Hi all, Please see below for an opportunity to present a poster at the CNS Open House. Best, Clare ________________________________ From: Wilson, William L <wwilson(a)cns.fas.harvard.edu> Sent: Thursday, October 19, 2023 10:13 AM To: Ploucha, Clare <cploucha(a)fas.harvard.edu>; Nishant Sule <nsule(a)g.harvard.edu> Cc: mikhail lukin <lukin(a)physics.harvard.edu>; Hu, Evelyn <ehu(a)seas.harvard.edu>; Park, Hongkun <hpark(a)fas.harvard.edu>; Loncar, Marko <loncar(a)seas.harvard.edu>; Machielse, Bart <bmachielse(a)g.harvard.edu>; Bhaskar, Mihir <mbhaskar(a)g.harvard.edu> Subject: FW: CNS Open House - Poster Request Hi Clare, I believe we have room for more posters for today’s Open House. Please circulate to your students and the Amazon team.. Best, Bill William L. Wilson PhD.  Executive Director Center for Nanoscale Systems  Faculty of Arts and Sciences | Harvard University  11 Oxford Street, LISE 308, Cambridge, MA 02138  Phone: (617) 495-3161 Fax: (617) 384-7302 Cell: (720) 841-3299  Email: wwilson(a)fas.harvard.edu<mailto:wwilson@fas.harvard.edu> [cid:image001.jpg@01D348AE.10153110] From: "Reynolds, James" <reynolds(a)cns.fas.harvard.edu> Date: Tuesday, October 17, 2023 at 3:48 PM To: "Reynolds, James" <reynolds(a)cns.fas.harvard.edu> Subject: CNS Open House - Poster Request All, Please submit a Poster for Thursday’s OpenHouse. Posters are welcome from “ALL” Users and Staff. Posters from external users are especially welcome. There will be poster awards. Looking forward to the session!! Best, Bill Wilson William L. Wilson Ph.D. Executive Director | Center for Nanoscale Systems (CNS) Faculty of Arts and Sciences | Harvard University 11 Oxford Street, LISE 308 Cambridge, MA 02138 Phone: (617) 495-3161 Cell: (720) 841-3299 FAX: (617) 384-7302 Email: wwilson(a)cns.fas.harvard.edu<mailto:wwilson@cns.fas.harvard.edu> [signature_1646808557] -- James Reynolds Assistant Director User Program Coordinator Center for Nanoscale Systems Harvard University 11 Oxford St., LISE 304 Cambridge, MA 02138 Ph: 617-384-7411 Fax: 617-384-7302 cns.fas.harvard.edu

6 months, 2 weeks

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TODAY: Harvard Quantum Information Seminar

by Cotler, Jordan Saul

Dear all, We are excited to have Greg Kahanamoku-Meyer from Lawrence Berkeley National Laboratory at the Harvard Quantum Information Seminar today at Jefferson Hall 250. The talk will start at 4:30 pm. Title - Quantum circuits for fast multiplication with few ancillas Abstract - Arithmetic on superpositions of numbers is a fundamental operation for many quantum algorithms. Multiplication in particular accounts for the vast majority of the cost of Shor's algorithm for factoring, as well as of recent protocols for efficiently-verifiable quantum advantage. The standard way of performing multiplication, both in the classical and quantum settings, requires O(n^2) gates, where n is the length of the inputs. Faster classical algorithms have been known for decades, but building quantum circuits based on them seems to require a large number of ancilla qubits. Here I present a technique for quantum multiplication which can achieve a sub-quadratic gate count using as few as just one ancilla qubit. I will discuss the algorithm itself and applications, showing to our knowledge the first implementation of Shor's algorithm that simultaneously uses fewer than O(n^3) gates and fewer than 3n total qubits. I will then discuss optimizations that can be applied in practice and present estimates of gate and qubit counts, showing that the algorithm is practical for realistic problem sizes. Hope to see you all there. Sincerely, Jordan Cotler

6 months, 2 weeks

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FW: [C2qa-communications-l] C2QA Quantum Thursdays Fall 2023 Flyer & Registration

by Ploucha, Clare

Please see below for a talk that may be of interest. From: C2QA-communications-l <c2qa-communications-l-bounces(a)lists.bnl.gov> on behalf of "Cusa, Donna via C2QA-communications-l" <c2qa-communications-l(a)lists.bnl.gov> Reply-To: "Cusa, Donna" <dcusa(a)bnl.gov> Date: Tuesday, October 17, 2023 at 1:01 PM To: "Cusa, Donna via C2QA-communications-l" <c2qa-communications-l(a)lists.bnl.gov> Subject: [C2qa-communications-l] C2QA Quantum Thursdays Fall 2023 Flyer & Registration [cid:image001.png@01DA00FA.482E0350] [Raymond SAMUEL | North Carolina Agricultural and Technical State University, North Carolina | NC A&T | Department of Biology | Research profile] Fall 2023 Educational and Outreach Series 12:00 – 1:00 p.m. ET Moderator Raymond E. Samuel, M.D., Ph.D. North Carolina Agricultural & Technical State University (C2QA Affiliate Member) Featuring the U.S. Department of Energy Quantum Information Science (QIS) Centers Quantum Thursdays focuses on bringing awareness to the undergraduate and graduate communities about quantum information science, the research being done in the five U.S. Dept. of Energy Quantum Centers, and the different career paths available in this field. REGISTER AT: https://bit.ly/QuantThurs<https://urldefense.proofpoint.com/v2/url?u=https-3A__bit.ly_QuantThurs&d=Dw…> Oct 26, 2023 [A person in a suit and tie Description automatically generated] Jonathan Marcks Q-NEXT Interfacing with Solid State Qubits Nov 2, 2023 [cid:image004.jpg@01DA00FA.482E0350] Silvia Zorzetti SQMS Research advances & opportunities in the National Quantum Information Science Research Centers Nov 9, 2023 [cid:image005.png@01DA00FA.482E0350] Huo Chen QSA Adaptive variational simulation for open quantum systems Nov 30, 2023 [A person in a blue sweater Description automatically generated] Vahagn Mkhitaryan QSC Quantum phases of Shastry-Sutherland lattice of Rydberg Atoms Dec 7, 2023 [cid:image007.jpg@01DA00FA.482E0350] Łukasz Dusanowski C2QA Individual Erbium Ions in Nanophotonic Structures for Quantum Networks Applications [cid:image008.png@01DA00FA.482E0350] Donna M. Cusa Co-Design Center for Quantum Advantage (C2QA) _______________________________________________________________________________________________________________________________________________________________________________________________________________________________ 40 Brookhaven Ave, Bldg. 460, Upton, NY 11973 - 5000 C: 646-369-2356 | E: dcusa(a)bnl.gov<mailto:dcusa@bnl.gov>

6 months, 3 weeks

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THIS THURSDAY: Harvard Quantum Information Seminar

by Cotler, Jordan Saul

Dear all, We are excited to have Greg Kahanamoku-Meyer from Lawrence Berkeley National Laboratory at the Harvard Quantum Information Seminar on October 19th at Jefferson Hall 250. The talk will start at 4:30 pm. Title - Quantum circuits for fast multiplication with few ancillas Abstract - Arithmetic on superpositions of numbers is a fundamental operation for many quantum algorithms. Multiplication in particular accounts for the vast majority of the cost of Shor's algorithm for factoring, as well as of recent protocols for efficiently-verifiable quantum advantage. The standard way of performing multiplication, both in the classical and quantum settings, requires O(n^2) gates, where n is the length of the inputs. Faster classical algorithms have been known for decades, but building quantum circuits based on them seems to require a large number of ancilla qubits. Here I present a technique for quantum multiplication which can achieve a sub-quadratic gate count using as few as just one ancilla qubit. I will discuss the algorithm itself and applications, showing to our knowledge the first implementation of Shor's algorithm that simultaneously uses fewer than O(n^3) gates and fewer than 3n total qubits. I will then discuss optimizations that can be applied in practice and present estimates of gate and qubit counts, showing that the algorithm is practical for realistic problem sizes. Hope to see you all there. Sincerely, Jordan Cotler

6 months, 3 weeks

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2024

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Qse-grad-students October 2023