aspuru-list September 2020

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

by Aram Harrow

Dear quanta, Tomorrow our speaker will be Giacomo who will tell us about his recent paper on quantum Wasserstein distance: https://arxiv.org/abs/2009.04469 Next week (Oct 2) will be Yichen who will tell us about his recent work on convergence to the thermodynamic limit in 1D systems. https://arxiv.org/abs/2009.05095 Both will be at the usual link: https://mit.zoom.us/j/97943342302 -aram _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

3 years, 6 months

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

by Aram Harrow

1. Sorry for my mistake about the day in Netta's talk on black holes. 2. There is another conference this week, on random quantum circuits https://www.pks.mpg.de/dcurqc20/program/ 3. See below for a talk by Soonwon on Mon, Oct 5. ---------- Forwarded message --------- From: Lesley Keaney <lkeaney(a)mit.edu> Date: Tue, Sep 29, 2020 at 8:54 AM Subject: [CMT Seminar] Chez Pierre seminar-Monday, October 5, 2020 (via Zoom) To: chezpierre <chezpierre(a)mit.edu>, cmt_seminar <cmt_seminar(a)mit.edu> Hello everyone, The next Chez Pierre Seminar for the Fall 2020 semester will be held on Monday, October 5, 2020 at 12:00pm noon EDT. The seminar will be broadcast via password protected Zoom link. The details are listed below. Soonwon Choi – Massachusetts Institute of Technology “Symmetry and information flow in quantum circuits with measurements” We will discuss novel quantum phases and phase transitions that emerge in the dynamics of quantum circuits and exhibit distinct modes of information flow. We consider a quantum system undergoing time evolution generated by random unitary gates which are occasionally interrupted by local measurements. It was previously found that such evolution leads to a phase transition in the entanglement of the wavefunction: at steady state it is characterized by volume law entanglement for small measurement rate, while it is an area law above a threshold rate. We investigate this phase transition by mapping the quantum dynamics into classical statistical mechanics models in equilibrium. Furthermore, we show that more phases are possible if we impose symmetries on the dynamics. To identify the phases, we develop a mapping between the dynamics in a broad class of quantum circuits to the ground states of effective spin Hamiltonians, which possess a higher symmetry than the original circuit. The different ground state phases admitted by the higher symmetry correspond to distinct patterns of information flow and scrambling in the circuit dynamics. We illustrate these ideas with two examples: (i) a quantum circuit with Z_2 symmetry resulting in non-abelian D_4 symmetry in an effective Hamiltonian and (ii) a quadratic fermionic circuit leading to U(1) symmetry. The latter exhibits Kosterlitz–Thouless transition in 1D between a critical phase with log(L) entanglement and "trivial" area law phases. Our work is a first step toward the classification of information flow in generic quantum circuits with symmetries. Talk: 12:00pm noon Date: Monday, October 5, 2020 Broadcast via: Zoom (details are listed below) Host: Senthil Todadri Time: October 5, 2020 12:00pm Eastern Time (US and Canada) Join Zoom Meeting: https://mit.zoom.us/j/98108729602?pwd=QXpCSkdBRVJWUkNFSWlOcnovMUFEZz09 Password: 799417 One tap mobile +16465588656,,98108729602# US (New York) +16699006833,,98108729602# US (San Jose) Meeting ID: 981 0872 9602 US : +1 646 558 8656 or +1 669 900 6833 International Numbers: https://mit.zoom.us/u/adC66pLaYX Join by SIP 98108729602(a)zoomcrc.com Join by Skype for Business https://mit.zoom.us/skype/98108729602Chez Pierre seminars are usually scheduled for Mondays at 12:00pm noon EDT. Seminar speakers, titles and abstracts will be posted on the Chez Pierre seminar website: http://web.mit.edu/physics/cmt/chezp.html. Thank you, Lesley Lesley Keaney Administrative Assistant Condensed Matter Theory Group MIT Department of Physics Room 6C-339 Cambridge, MA 02139 617.253.4878 (phone); 617.253.2562 (fax) _______________________________________________ CMT_seminar mailing list CMT_seminar(a)mit.edu http://mailman.mit.edu/mailman/listinfo/cmt_seminar _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

3 years, 6 months

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

by Aram Harrow

Dear quanta, The next few days (starting tomorrow) will be a workshop on the 'informational lens' with a focus tomorrow on quantum, including a talk by me that will probably be already familiar material for most of you. https://sites.google.com/view/informational-lens-workshop-1/home?authuser=0 --- At 2pm tomorrow there is a nuclear/particle theory seminar on the black hole information problem. “The Black Hole Information Paradox: A Resolution on the Horizon?” Abstract: The black hole information paradox — whether information escapes an evaporating black hole or not — remains one of the greatest unsolved mysteries of theoretical physics. The apparent conflict between validity of semiclassical gravity at low curvatures and unitarity of quantum mechanics has long been expected to find its resolution in the deep quantum gravity regime. Recent developments in the holographic dictionary and in particular its application to entanglement, however, have shown that a semiclassical analysis of gravitational physics has a hallmark feature of unitary evolution. I will describe this recent progress and discuss some potential new avenues for working towards a resolution of the information paradox. https://mit.zoom.us/j/92926107078?pwd=MUdQeHNFVUhJbDhneEREWm9KQ2FPdz09 Meeting ID: 929 2610 7078 Password: MIT-CTP-NP --- Thursday at 4pm is the Physics Colloquium Speaker: Frank Wilczek, MIT Title: “Quanta of the Third Kind: Anyons” Abstract: According to traditional understanding, quantum particles are either bosons or fermions. This so-called “quantum statistics” has important consequences for their behavior. In the late 70-ies the mathematics of topology was employed to get a deep understanding of quantum statistics, and lead to the realization that in two spatial dimensions there are alternatives beyond bosons and fermions. The new possible particles go under the general name “anyons”, coined in 1982. In 1984 it was demonstrated, theoretically, that quasiparticles in the states of matter known as fractional quantum Hall liquids (FQHL) are fractionally charged anyons. Since then, theoretical and numerical work on states of two-dimensional matter has predicted many types of anyons, and in particular “nonabelian” anyons that could be a powerful resource for quantum computers. Until very recently, experiments on anyons lagged far behind the thriving theoretical and numerical work, but this spring, two independent innovative experiments convincingly observed anyon behavior in the simplest FQHL. The age of experimental anyonics is upon us. LINK: https://mit.zoom.us/j/93759934137?pwd=cFRuTTRGS1Y1eWxIQUNYblZlbVlVdz09 Password: phys82020 --- And finally, this Friday we will have Yichen speak in our group meeting about his work on convergence to the thermodynamic limit. aram _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

3 years, 6 months

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

by Aram Harrow

Dear quanta, Tomorrow (11am ET) we'll have Karen Morenz tell us about her work on better-than-product-state approximations for the antiferromagnetic Heisenberg model on general graphs. Here is the zoom link https://mit.zoom.us/j/97943342302 and the paper https://arxiv.org/abs/2003.14394 Sep 11 we will have Ike tell us about q algorithms. Sep 18 we will have Michael Kreshchuk (Tufts) tell us about simulating molecules and high-energy physics. -aram _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

3 years, 7 months

[Aspuru-Guzik Group List] [qip] Fwd: Funded postdoctoral and PhD positions in quantum error correction

by Aram Harrow

postdoc opening in Berlin, due in 2 weeks. ---------- Forwarded message --------- From: Jens Eisert <jense(a)zedat.fu-berlin.de> Date: Mon, Sep 14, 2020 at 6:34 AM Subject: Funded postdoctoral and PhD positions in quantum error correction To: Jens Eisert <jense(a)physik.fu-berlin.de> We are offering both a fully funded three-year postdoctoral position (E13) and a PhD position (E13 3/4) to highly motivated and well-qualified researchers who intend to conduct research in the field of quantum error correction and related fields. The scientific project will relate to the fundamentals of topological quantum error correcting codes as well as to near-term error mitigation in realistic quantum devices. The successful candidates will work as part of the research group led by Jens Eisert at the FU Berlin. For an overview of research activities, see http://www.physik.fu-berlin.de/en/einrichtungen/ag/ag-eisert/research We are a highly active research group with a culture of open discussion, creative interdisciplinary thought and substantial international collaborations. We also have a strong track record in supporting academic careers, see http://www.physik.fu-berlin.de/en/einrichtungen/ag/ag-eisert/people/past The positions have connections to the German BMBF initiative on quantum software, the European Quantum Flagship and the excellence initiative MATH+. All applications should be sent in electronic form to jense(a)physik.fu-berlin.de with the key word "QuantumErrorCorrection2020" in the subject line. Review of the applications will begin after September 28, 2020 and will continue until the positions are filled. Early submissions are appreciated. The start date is flexible. -- Jens Eisert Professor of Quantum Physics Dahlem Center for Complex Quantum Systems Physics Department Freie Universität Berlin Arnimallee 14, 14195 Berlin jense(a)physik.fu-berlin.de http://www.physik.fu-berlin.de/qmio http://scholar.google.de/citations?user=WawCci0AAAAJ&hl=en https://twitter.com/jenseisert _______________________________________________ qip mailing list qip(a)mit.edu http://mailman.mit.edu/mailman/listinfo/qip

3 years, 7 months

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aspuru-list September 2020