Simons Collaboration on It from Qubit Annual Meeting 2021

Date & Time


Gerald D. Fischbach Auditorium
160 5th Ave
New York, NY 10010 United States

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Thurs.: 8:30 AM—5 PM
Fri.: 8:30 AM—2 PM

Registration Closed

Invitation Only

Participation is by invitation only. All participants must register.

Patrick Hayden, Stanford University
Matthew Headrick, Brandeis University

Meeting Goals:
The 2021 annual meeting will be devoted to recent developments at the interface of fundamental physics and quantum information theory, spanning topics such as chaos and thermalization in many-body systems and their realization in quantum gravity; wormholes and their information-theoretic implications; calculable lower-dimensional models of quantum gravity; the entanglement structure of semi-classical states in quantum gravity; complexity in field theory and gravity; the black-hole information puzzle; and theoretical and experimental aspects of quantum simulation and measurement-induced phase transitions.

Past Meetings:


Daniel Harlow, MIT
Alexei Kitaev, Caltech
Nima Lashkari, Purdue University
Juan Maldacena, IAS
Rob Myers, Perimeter Institute
Crystal Noel, Duke University
Brian Swingle, Brandeis University

  • Agendaplus--large

    Thursday, December 9

    9:30 AMRob Myers | Complexity Equals (Anything)^2
    10:30 AMBREAK
    11:00 AMNima Lashkari | Renormalization Group and Error Correction
    12:00 PMLUNCH
    1:00 PMCrystal Noel | Observation of a Quantum Phase Transition on a Trapped Ion Quantum
    2:00 PMBREAK
    2:30 PMPoster Session | IFQ Postdocs
    3:30 PMBREAK
    4:00 PMDaniel Harlow | Quantum Error Correction and the Page Curve

    Friday, December 10

    9:30 AMBrian Swingle | Hydrodynamics and Random Matrix Theory
    10:30 AMBREAK
    11:00 AMAlexei Kitaev | Out-of-Time-Order Correlators: A Two-Way Approach
    12:00 PMLUNCH
    1:00 PMJuan Maldacena | String Scale Black Holes
  • Abstractsplus--large

    Daniel Harlow
    Massachusetts Institute of Technology

    Quantum Error Correction and the Page Curve

    Harlow will discuss some new ideas on how to think about the emergence of the black hole interior for an old black hole.

    Alexei Kitaev
    California Institute of Technology

    Out-of-Time-Order Correlators: A Two-Way Approach

    Chaos in quantum many-body systems is described by out-of-time-order correlators (OTOCs) of four operators. One may regard two of them as a perturbation source and two others as a probe. A standard approach is to replace the actual source with some classical perturbation and to solve for the probe correlation function on the double Keldysh contour. In this talk, Kitaev shows how to obtain the OTOC by combining two such solutions, for perturbations propagating forward and backward in time. (This is a joint work with Yingfei Gu and Pengfei Zhang, currently in preparation.)

    Nima Lashkari
    Purdue University

    Renormalization Group and Error Correction

    In renormalization group (RG) flow, the low energy states form a code subspace that is protected against the local short-distance errors. Lashkari will discuss the similarities and differences between this approximate error correction code and the classical and quantum codes that appear in the degenerate vacua of local many-body quantum systems. Lashkari will consider continuous MERA as a concrete example and discuss how well the low-energy operators are protected. The trade-off bounds set a bound on the amount of quantum information at a scale. Finally, Lashkari will comment on the connections to the quantum error correction codes in holography and the high-energy states of chaotic quantum systems.

    Juan Maldacena
    Institute for Advanced Study

    String Scale Black Holes

    Maldacena will explore the transition between small black holes and string states. He will show that they are not continuously connected as classical solutions in the type II string theory but they are in the heterotic case. Maldacena will also discuss applications to some charged black holes.

    Rob Myers
    Perimeter Institute

    Complexity Equals (Anything)^2

    Myers will present a new infinite class of gravitational observables in asymptotically anti-de Sitter space living on codimension-one slices of the geometry, the most famous of which is the volume of the maximal slice. These observables display universal features for the thermofield double state: they grow linearly in time at late times and reproduce the switchback effect in shock wave geometries. Hence any member of this class of observables is just as good a candidate as the extremal volume for a gravitational dual of complexity.

    Crystal Noel
    Duke University

    Observation of a Quantum Phase Transition on a Trapped Ion Quantum Computer

    In this talk, Noel will introduce our trapped ion quantum computer based on 171Yb+ clock qubits (previously at University of Maryland and now located at the new Duke Quantum Center). The system is a fully connected random-access universal quantum computer with up to 13 qubits in regular operation and individual addressing of each qubit. Noel will describe experiments designed to explore open quantum systems via random quantum circuits. Here, the system evolution is represented by unitary gates with interspersed projective measurements. As the measurement rate is varied, a purification phase transition is predicted to emerge at a critical point, akin to a fault-tolerant threshold. Noel finds evidence of the phases associated with the transition and show numerically that, with modest system scaling, critical properties of the transition emerge. Finally, Noel will highlight other recent applications using the system and give an outlook for the future of ion trap quantum computing.

    Brian Swingle
    Brandeis University

    Hydrodynamics and Random Matrix Theory

    Ensembles of quantum chaotic systems are expected to exhibit random matrix universality in their energy spectrum. The presence of this universality can be diagnosed by looking for a linear in time ‘ramp’ in the spectral form factor, but for realistic systems, this feature is typically only visible after a sufficiently long time. It is important to understand the emergence of this universality and how it connects to the larger body of phenomena associated with quantum chaos. This talk will present a hydrodynamic theory of the spectral form factor in systems with slow modes. The formalism predicts the linear ramp at sufficiently late time and gives a quantitative framework for computing the approach to ramp.

  • Simons Foundation Lecture: December 8, 2021plus--large

    5:00-6:15 PM

    A public lecture will be presented the evening before the official start of the conference. Participants are encouraged to register and attend should their travel and other schedules align.

    Simons Foundation Lectures are free public colloquia related to basic science and mathematics. These high-level talks are intended for professors, students, postdocs and business professionals, but interested people from the metropolitan area are welcome as well.

    More information is available at the lecture’s page.

    Participation is optional; separate registration is required.

    Vijay Balasubramanian
    University of Pennsylvania

    Complexity, Quantum Mechanics and the Structure of Space-Time

    Quantum mechanics and general relativity are the two pillars of 20th-century physics. However, paradoxes arise when we attempt to combine these theories to arrive at a quantum theory of space and time, often because the appearance of black holes and spacetime singularities seem to destroy quantum information.

    In this lecture, Vijay Balasubramanian will discuss how we can resolve these paradoxes by drawing on concepts of complexity and information from theoretical computer science, communications theory and cryptography. He will use techniques from these fields to explain diverse, interlinked aspects of fundamental physics, including: the dynamics of quantum chaos and thermalization; the recovery of information from beyond the horizon of black holes; and, most fundamentally, causality in physical processes.

    To attend this in-person event, you will need to register in advance and provide:

    • Acceptable proof of vaccination (vaccine card/certificate, a copy or photo of vaccine card/certificate or electronic NYS Excelsior Pass or NJ Docket Pass)
    • Photo ID
    • Eventbrite ticket confirmation email with QR code
    • Simons Foundation Health Screening Questionnaire approval email

    Guests are expected to complete these requirements each time they visit the Simons Foundation and entrance will not be granted without this documentation.

    On-site registration will not be permitted. Walk-in entry will be denied.

  • Participation & Fundingplus--large

    Participation in the meeting falls into the following four categories. An individual’s participation category is communicated via their letter of invitation.

    Group A – PIs and Speakers
    The foundation will arrange and pay for all air and train travel to the conference as well as hotel accommodations and reimbursement of local expenses. Business-class or premium economy airfare will be booked for all flights over five hours.

    Group B – Out-of-town Participants
    The foundation will arrange and pay for all air and train travel to the conference as well as hotel accommodations and reimbursement of local expenses. Economy-class airfare will be booked for all flights.

    Group C – Local Participants
    Individuals in Group C will not receive financial support, but are encouraged to enjoy all conference-hosted meals.

    Group D – Remote Participants
    Individuals in Group D will participate in the meeting remotely. Please register at the link above and a remote participation link will be sent to you approximately two weeks prior to the meeting.

  • Travel & Hotelplus--large

    Air and Train
    The foundation will arrange and pay for all air and train travel to the conference for those in Groups A and B. Please provide your travel specifications by clicking the registration link above. If you are unsure of your group, please refer to your invitation sent via email.

    Personal Car
    For participants in Groups A & B driving to Manhattan, The James NoMad Hotel offers valet parking. Please note there are no in-and-out privileges when using the hotel’s garage, therefore it is encouraged that participants walk or take public transportation to the Simons Foundation.

    Participants in Groups A & B who require accommodations are hosted by the foundation for a maximum of three nights at The James NoMad Hotel. Any additional nights are at the attendee’s own expense. To arrange accommodations, please register at the link above.

    The James NoMad Hotel
    22 E 29th St
    New York, NY 10016
    (between 28th and 29th Streets)

    For driving directions to The James NoMad, please click here.

  • COVID-19 Policyplus--large

    ALL in-person meeting attendees must be vaccinated against the COVID-19 virus with a World Health Organization approved vaccine, be beyond the 14-day inoculation period of their final dose, and provide proof of vaccination upon arrival to the conference. Acceptable vaccines can be found at the bottom of this page on WHO’s site.

  • Reimbursementplus--large

    Individuals in Groups A & B will be reimbursed for meals not hosted by the Simons Foundation as well as local expenses, including ground transportation. Additional information in this regard will be emailed on the final day of the meeting.

  • Contactsplus--large

    Travel & Hotel Assistance
    Ovation Travel Team

    Meeting Questions & Assistance
    Meghan Fazzi
    Manager, Events and Administration, MPS, Simons Foundation
    (212) 524-6080

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