aspuru-list September 2019

aspuru-list@lists.fas.harvard.edu

3 participants
14 discussions

[Aspuru-Guzik Group List] Joint Quantum Seminar - Wednesday, October 2 @ 4:00 - Prof. Marcello Dalmonte

by Ploucha, Clare

Joint Quantum Seminar Wednesday, October 2nd 4:00 PM, Jefferson 250 Prof. Marcello Dalmonte, ICTP “Quantum simulating lattice gauge theories: ‘particle physics’ with Rydberg atom arrays” Gauge theories are the back-bone of our understanding of nature at the most fundamental level as captured by the standard model. Despite their elegance and conceptual simplicity, gauge theories have historically represented a major computational challenge in many-body theory - including, for instance, the real-time dynamics describing heavy-ion collisions at colliders, which is inaccessible to classical simulations based on Monte Carlo sampling. These challenges have motivated a flurry of theoretical activity over the last ten years, devoted at developing strategies for the quantum simulation of their discretized version - lattice gauge theories. In this first part of the talk, I will review the status of the field, highlighting potential applications as well as roadblocks, and discussing the first realization of gauge theory dynamics in a trapped ion quantum computer. In the second part of the talk, I will show how Rydberg atoms trapped in optical tweezers offer unprecedented opportunities for the realization of lattice gauge theories in AMO systems. In particular, I will describe how recent experiments have already realized the real-time dynamics of the lattice Schwinger model (the one-dimensional version of quantum electrodynamics) in the presence of a topological angle. Beyond demonstrating that quantum simulation of gauge theory is an experimental reality at large scales, the analogy between Rydberg atom arrays and gauge theories provides a powerful field theoretical tool to understand the slow-dynamics describing such systems - that immediately opens the door for its generalization to other models sharing the same field theoretical description. Finally, I will describe how other archetypical physical phenomena of lattice gauge theories - such as the effect of confinement on the dynamics, and the evolution of mesons - can be observed within the same platform. 4:00 pm: 10-minute Talk 4:10 pm: Refreshments 4:30 pm: Prof. Dalmonte -- Clare Ploucha Director of Programs Harvard Quantum Initiative 17 Oxford Street, Jefferson 357 Cambridge, MA 02138 P: 617-495-3388

4 years, 7 months

[Aspuru-Guzik Group List] [qip] group meeting tomorrow

by Aram Harrow

Dear quanta, Let's meet tomorrow at 11am in 6-310. We'll plan to go around the room and have each person talk for 2-3 minutes about what they have been thinking about lately. aram _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 7 months

[Aspuru-Guzik Group List] Joint Quantum Seminar - TODAY @ 4:00 - Prof. Maria Spiropulu

by Ploucha, Clare

Joint Quantum Seminar Wednesday, September 25 4:00 PM, Jefferson 250 Prof. Maria Spiropulu Caltech “Quantum Networks: technologies and fundamental science” The talk will discuss technology leaps on components of quantum networks (e.g., detectors, sources), progress on quantum networking systems and the connection with fundamental research on the possible quantum nature of space-time/gravity and dark matter. 10-Minute Talk by Mihir Bhaskar (Lukin group) “Experimental demonstration of memory-enhanced quantum communication” 4:00 pm: 10-minute Talk 4:10 pm: Refreshments 4:30 pm: Prof. Spiropulu -- Clare Ploucha Director of Programs Harvard Quantum Initiative 17 Oxford Street, Jefferson 357 Cambridge, MA 02138 P: 617-495-3388

4 years, 7 months

[Aspuru-Guzik Group List] [qip] Oct 16-18 Workshop on Noncommutative Analysis, Computational Complexity, and Quantum Information

by Aram Harrow

see below for an announcement for an upcoming conference at Harvard ----------- Bill Helton, Pablo Parrilo, Tselil Schramm and Pablo Parrilo will be organizing a workshop on "Noncommutative Analysis, Computational Complexity, and Quantum Information" in the CMSA on October 16-18, see http://cmsa.fas.harvard.edu/noncommutative-analysis/ This is an area that has brings together optimization, algebra, complexity, quantum information, and more, and we have a great set of exciting speakers. We will also start off on Wednesday (October 16th) with some tutorials to get everyone familiar with the different topics. Check out the website http://cmsa.fas.harvard.edu/noncommutative-analysis/ which will be updated with more information on talks and schedule in the next few weeks. _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 7 months

[Aspuru-Guzik Group List] [qip] CUA seminar at Harvard on Tues, Sep 24, 4pm

by Aram Harrow

TUE SEPTEMBER 24, 2019 4:00 PM Dynamics of quantum systems with long-range interactions Location:Harvard Jefferson 250 Alexey Gorshkov, University of Maryland Ten Minute Talk:"High-fidelity multi-qubit gates with neutral atoms" by Harry Levine Atomic, molecular, and optical systems often exhibit long-range interactions, which decay with distance r as a power law 1/r^alpha. In this talk, we will derive bounds on how quickly quantum information can propagate in such systems. We will then discuss applications of these bounds to numerous phenomena including classical and quantum simulation of quantum systems, prethermal phases in Floquet systems, entanglement area laws, sampling complexity, and scrambling. http://www.rle.mit.edu/cua_responsive/events/alexey-gorshkov-cua-seminar/ _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 7 months

[Aspuru-Guzik Group List] Joint Quantum Seminar - Wednesday, September 25 @ 4:00 - Prof. Maria Spiropulu

by Ploucha, Clare

Joint Quantum Seminar Wednesday, September 25 4:00 PM, Jefferson 250 Prof. Maria Spiropulu Caltech TITLE AND ABSTRACT TBA 10-Minute Talk by Mihir Bhaskar (Lukin group) “Experimental demonstration of memory-enhanced quantum communication” 4:00 pm: 10-minute Talk 4:10 pm: Refreshments 4:30 pm: Prof. Spiropulu

4 years, 7 months

[Aspuru-Guzik Group List] [qip] QI seminar this Friday, 1:30pm, 6c-442, Jeremy Butterfield

by Aram Harrow

This Friday we have Seth's former advisor Jeremy Butterfield visiting. https://en.wikipedia.org/wiki/Jeremy_Butterfield He works on philosophy of physics and during the 11am group meeting will tell us about his work on symmetry and duality. He will also give a talk at 1:30pm in room 6c-442. Here are the details. title: Deriving time evolution in general relativity : a philosopher's perspective. Joint work with Henrique Gomes, Cambridge. Abstract: Abstract: This talk will advertise three results that give, in a broadly general-relativistic framework, sufficient conditions for time-evolution being generated by the ADM Hamiltonian. The philosophical background is functionalism. Roughly speaking, it is the idea that one specifies an entity or concept by its web of relations to other entities and concepts. Recently philosophers have debated 'spacetime functionalism': "spacetime is as spacetime does". Thus their focus is on how the physics of matter and radiation contributes to determining, or perhaps even determines or explains, chrono-geometry: a Machian theme. The results are as follows:--- (i) The recovery of geometrodynamics, i.e. general relativity's usual ADM Hamiltonian, from requirements on deformations of hypersurfaces in a Lorentzian spacetime; due to Hojman, Kuchar and Teitelboim (1976: Annals of Physics); (ii) The deduction from judicious assumptions about matter and radiation in a 4-dimensional manifold that there is an (appropriately related) Lorentzian metric; due to Schuller, Duell, Giesel et al. (2012, 2018: Physical Review D); (iii) The deduction of a Lorentzian metric and of general relativity's usual ADM Hamiltonian, assuming (not a 4-manifold: but merely) that how a 3-geometry changes over time should be locally definable (Gomes and Shyam 2016: Journal of Mathematical Physics; and at 1608.08236). Thus the overall aim of the talk is to give a philosophical background to Gomes and Shyam, 1608.08236. _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 7 months

[Aspuru-Guzik Group List] [qip] tomorrow 1pm: EPiQC remote talk on simulating quantum circuits

by Aram Harrow

This will be in 6-310 and we will stream it from Chicago. This is part of our EPIQC collaboration but anyone is welcome to attend. title: Bayesian Network Knowledge Compilation for Quantum Circuit Simulation speaker: Yipeng Huang Abstract: The problem of simulating quantum circuits that appear in variational algorithms offers distinct opportunities, when compared to simulating other types of quantum circuits. We focus on exploiting three characteristics common in variational algorithm quantum circuits. These properties are 1. circuits in variational algorithms such as VQE and QAOA are often wide but shallow, 2. the algorithms run circuits with the same topology many times, with only differences in gate parameters between runs, 3. the variational algorithm expects the quantum computer or simulator to return samples from a multi-modal wavefunction, and not the full high-dimensional wavefunction. These traits make this type of circuit simulation a distinctive workload compared to simulating Shor's, Grover's, or even random circuit sampling workloads. In this ongoing work, we use knowledge compilation on Bayesian networks to aid simulating variational quantum algorithms. Knowledge compilation is a set of techniques we borrow from classical AI inference, which had been useful for repeated inference on AI models with different parameters, and for efficient stochastic simulation of those inference models. Those tricks may be useful here for quantum circuit simulation. The toolchain begins by converting quantum circuits to complex-valued Bayesian networks. This transformation has been established by prior work that use probabilistic graphical models and tensor network contraction for quantum circuit simulation. From this transformation, our work strikes out on a new pathway to do simulation. We convert the Bayesian networks to conjunctive normal forms, and finally to arithmetic circuits for inference. These minimized arithmetic circuits can be reused across multiple simulations with different parameters. Furthermore, the arithmetic circuits allow for more efficient sampling of measurement outcomes from the final wavefunction. We experimentally validate our simulation toolchain using Google Cirq for its QAOA benchmark, its simulator test harnesses, and its native simulator as a baseline. We are able to beat the native simulator for QAOA problem sizes beyond 16 qubits, where the native simulator starts to struggle with longer wavefunction vectors. Our proposed approach appears to be limited in terms of depth to about 33 steps, where the size of the compiled topology becomes a limiting factor. In all, the approach may be useful in simulating this wide but shallow range of quantum circuits. _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 7 months

[Aspuru-Guzik Group List] [qip] group meeting tomorrow

by Aram Harrow

Dear quanta, We will meet at 11am tomorrow in 6-310. Nilin will tell us about his work on Hamiltonians on trees. -aram _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 7 months

[Aspuru-Guzik Group List] Joint Quantum Seminar - TODAY @ 4:30 - Prof. Markus Aspelmeyer

by Ploucha, Clare

Joint Quantum Seminar Wednesday, September 11 4:00 PM, Jefferson 250 **NOTE: No 10-Minute Talk. Speaker will begin at 4:30pm** Prof. Markus Aspelmeyer University of Vienna Institute for Quantum Optics and Quantum Information (IQOQI) , Austrian Academy of Sciences “Quantum Optical Control of Levitated Solids: a novel probe for the gravity-quantum interface” The increasing level of control over motional quantum states of massive, solid-state mechanical devices opens the door to an hitherto unexplored parameter regime of macroscopic quantum physics. I will report on our recent progress towards controlling levitated solids in the quantum regime. I will discuss the prospects of using these systems for fundamental tests of physics, including the interface between quantum and gravitational physics. 4:00 pm: Refreshments 4:30 pm: Prof. Aspelmeyer -- Clare Ploucha Director of Programs Harvard Quantum Initiative 17 Oxford Street, Jefferson 357 Cambridge, MA 02138 P: 617-495-3388

4 years, 7 months

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aspuru-list September 2019