aspuru-list November 2019

aspuru-list@lists.fas.harvard.edu

2 participants
11 discussions

[Aspuru-Guzik Group List] [qip] talk on Mon, Dec 2

by Aram Harrow

Dear quanta, There is no meeting this week because of Thanksgiving. Next week, we will have a special seminar on Monday by Marissa Giustina on Google's hardware. --------- Monday December 2, 2019 11:00 6C-442 Title: Building Google’s Quantum Computer Presenter: Marissa Giustina, Senior Research Scientist and Quantum Electronics Engineer, Google LLC. Abstract: The Google AI Quantum team develops chip-based circuitry that one can interact with (control and read out) and which behaves reliably according to a simple quantum model. Such quantum hardware holds promise as a platform for tackling problems intractable for classical computing hardware. While the demonstration of a universal, fault-tolerant, quantum computer remains a goal for the future, it has informed the design of a prototype with which we have recently controlled a quantum system of unprecedented scale. This talk introduces Google’s quantum computing effort from both hardware and quantum-information perspectives, including an overview of recent technological developments and recent results. _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 4 months

[Aspuru-Guzik Group List] [qip] talks this week

by Aram Harrow

Wed at 1pm we will have a remote talk from Ken Brown about our STAQ collaboration. This will be a broad overview of work on quantum algorithms and architectures. The Thursday physics colloquium (4pm, 10-250) should interest some of us. It is "Quantum Simulation of Abelian and non-Abelian Gauge Theories" by Uwe-Jens Wiese. https://web.mit.edu/physics/events/colloquia.html Fri at 11am we will have Yi-Xiang Liu from the Cappellaro group speaking at the group meeting about q simulation. Below are her title & abstract. Title: High-fidelity Trotter expansions for digital quantum simulation Abstract: Quantum simulation promises to address many challenges in fields ranging from quantum chemistry to material science and high-energy physics, and could be implemented in noisy intermediate scale quantum devices. A challenge in building good digital quantum simulators is the fidelity of the engineered dynamics given a finite set of elementary operations. The goal of this work is to find a proper ordering of elementary operations (Trotter expansion), so that they approximate as well as possible the desired evolution. However, when the quantum system is large, even calculating one elementary operation is computationally expensive. In this talk I will introduce a geometric framework for optimizing the order of operations without considering the details of the operations themselves, thus achieving computational efficiency. Based on the geometric framework, I will present two alternative orderings. One has optimal fidelity at a short time scale, and the other one is robust at a long time scale. Thanks to the improved fidelity at different time scales, the two different orderings can form the basis for experimental-constrained digital quantum simulation. https://arxiv.org/abs/1903.01654 _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 4 months

[Aspuru-Guzik Group List] Special Seminar - TODAY @ 3PM - Jeremy Young

by Ploucha, Clare

HQI Special Seminar Thursday, November 21 3:00 PM, Jefferson 356 Jeremy Young (UMD), Postdoc Candidate Driven-dissipative coupled Ising models: a new non-equilibrium universality class Driven-dissipative systems can potentially exhibit non-equilibrium phenomena that are absent in their equilibrium counterparts. However, phase transitions present in these systems generically exhibit an effectively classical, equilibrium behavior in spite of their non-equilibrium origin. To illustrate this, I will begin by showing how the driven-dissipative Bose-Hubbard model gives rise to emergent thermal behavior near the critical point. I will then investigate an experimentally-motivated model where two Ising-like order parameters interact and form a multicritical point and discuss how at such a multicritical point, new non-equilibrium criticality can emerge. These non-equilibrium multicritical points exhibit a variety of exotic phenomena with no counterpart in equilibrium, including spiraling phase boundaries, the emergence of discrete scale invariance rather than the more familiar continuous scale invariance, and the violation of the fluctuation-dissipation theorem at all length scales, resulting in a sytem which becomes “hotter” and “hotter” at longer and longer wavelengths. Finally, I will discuss some future directions based on these results, such as non-equilibrium quantum criticality.

4 years, 4 months

[Aspuru-Guzik Group List] HQI Special Seminar - TODAY @ 12PM - Prof. Vahid Sandoghdar

by Ploucha, Clare

HQI Special Seminar Wednesday, November 20 12 PM, Jefferson 250 Lunch will be served Prof. Vahid Sandoghdar, Max Planck Institute for the Science of Light Efficiency in the Interaction of Light and Matter: From Nano-quantum Optics to Nanobiophotonics Light-matter interaction at the nanometer scale lies at the heart of elementary optical processes such as absorption, emission or scattering. Over the past two decades, we have realized a series of experiments to investigate the interaction of single photons, single molecules and single nanoparticles. In this presentation, I will report on recent studies, where we reach unity efficiency in the coupling of single photons to single molecules and describe our efforts to exploit this for the realization of polaritonic states involving a controlled number of molecules and photons. Furthermore, I will show how the underlying mechanisms that play a central role in quantum optics, help image and track single biological nanoparticles such as viruses and small proteins with high spatial and temporal resolutions. -- Clare Ploucha Director of Programs Harvard Quantum Initiative 18 Hammond Street, Palfrey 105 Cambridge, MA 02138

4 years, 4 months

[Aspuru-Guzik Group List] Special Seminar - Thursday, November 21 @ 3PM - Jeremy Young

by Ploucha, Clare

4 years, 5 months

[Aspuru-Guzik Group List] HQI Special Seminar - Wednesday, November 20 @ 12PM - Prof. Vahid Sandoghdar

by Ploucha, Clare

4 years, 5 months

[Aspuru-Guzik Group List] [qip] group meeting and afternoon talk tomorrow

by Aram Harrow

Dear quanta, Tomorrow at 11am we will meet in 6-310 and our visitor Ulysse Chabaud will tell us about his recent work on the stellar representation of non-Gaussian states. https://arxiv.org/abs/1907.11009 At 1:30pm, Giacomo will give a talk in 6c-402 about optimal transport in quantum systems. https://arxiv.org/abs/1911.00803 -aram _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 5 months

[Aspuru-Guzik Group List] [qip] Ulysse Chabaud visit

by Aram Harrow

Dear quanta, Ulysse Chabaud is visiting us from Paris 6 from this afternoon through Friday. He'll speak on Friday about "the stellar representation of non-Gaussian states" and his other work is generally on the continuous-variable side of quantum information. If you would like to meet him, you can either email me, or write him directly at ulysse.chabaud(a)gmail.com. He'll be in 6-308 while here. His papers are here: https://scholar.google.com/citations?user=ro1eG-EAAAAJ&hl=fr -aram _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 5 months

[Aspuru-Guzik Group List] Joint Quantum Seminar - Wednesday, November 13 @ 12PM - Prof. Michelle Simmons

by Ploucha, Clare

Joint Quantum Seminar Wednesday, November 13 12 PM, Jefferson 250 *PLEASE NOTE SPECIAL TIME* Michelle Simmons - Centre of Excellence for Quantum Computation and Communication Technology, University of New South Wales Atomic qubits in silicon Abstract: Building a quantum computer in the highly manufacturable material silicon offers many advantages. Phosphorus atom qubits in silicon in particular have demonstrated extremely long (up to 35 s) coherence times with >99.9% fidelity. Their small size, combined with the magnetically quiet environment of isotopically pure silicon, make them analogous to ion trap qubits but in a scalable solid-state system. One of the challenges for semiconductor qubits is to understand how to engineer and control qubit initialisation, read-out and coupling at nm length scales. Scanning probe techniques, combined with molecular beam epitaxy allow us to realise fully crystalline devices at the atomic scale and directly probe the qubit wave function with exquisite precision. We will discuss the ability to scale atomic qubits and long term vision for this approach.

4 years, 5 months

[Aspuru-Guzik Group List] [qip] talks Friday

by Aram Harrow

Dear quanta, In our Friday group meeting we will have a talk from Kyungjoo Noh (Yale) on bosonic codes. That afternoon (1:30pm, 6c-402) we will have a talk by Tongyang Li (Maryland); information below. Title: Quantum algorithm for estimating volumes of convex bodies https://arxiv.org/abs/1908.03903 Abstract: Estimating the volume of a convex body is a central problem in convex geometry and can be viewed as a continuous version of counting. We present a quantum algorithm that estimates the volume of an $n$-dimensional convex body within multiplicative error $\epsilon$ using $\tilde{O}(n^{3}+n^{2.5}/\epsilon)$ queries to a membership oracle and $\tilde{O}(n^{5}+n^{4.5}/\epsilon)$ additional arithmetic operations. For comparison, the best known classical algorithm uses $\tilde{O}(n^{4}+n^{3}/\epsilon^{2})$ queries and $\tilde{O}(n^{6}+n^{5}/\epsilon^{2})$ additional arithmetic operations. To the best of our knowledge, this is the first quantum speedup for volume estimation. Our algorithm is based on a refined framework for speeding up simulated annealing algorithms that might be of independent interest. This framework applies in the setting of "Chebyshev cooling", where the solution is expressed as a telescoping product of ratios, each having bounded variance. We develop several novel techniques when implementing our framework, including a theory of continuous-space quantum walks with rigorous bounds on discretization error. _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

4 years, 5 months

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aspuru-list November 2019