There are no events at the Simons Center today. Here are the events for this week
Monday, June 1st, 2026
YITP Event: YITP Seminar Speaker: Liyuan Chen Harvard
Time: 11:00 AM - 12:00 PM
Location:
Title: Toward a practical topological quantum computer Â
Abstract: Topological quantum computation with non-Abelian codes offers a compelling path to reliable quantum processors. However, the practical realization of this scheme remains an open question due to a lack of fault-tolerant realization. I will present our solution---a concrete two-dimensional architecture based on the quantum double model D(S3) that delivers fault-tolerant universality without magic-state distillation [npj Quantum Information 11, 112 (2025)]. Assuming an efficient decoder, our approach implements a fault-tolerant universal gate set using devices available on today’s quantum platforms. The current progress on constructing a fault-tolerant quantum error correction scheme and the error proliferation in (un)gauging such semi-direct-product-based non-Abelian codes are also discussed.
Title: Toward a practical topological quantum computer Â
Abstract: Topological quantum computation with non-Abelian codes offers a compelling path to reliable quantum processors. However, the practical realization of this scheme remains an open question due to a lack of fault-tolerant realization. I will present our solution---a concrete two-dimensional architecture based on the quantum double model D(S3) that delivers fault-tolerant universality without magic-state distillation [npj Quantum Information 11, 112 (2025)]. Assuming an efficient decoder, our approach implements a fault-tolerant universal gate set using devices available on today’s quantum platforms. The current progress on constructing a fault-tolerant quantum error correction scheme and the error proliferation in (un)gauging such semi-direct-product-based non-Abelian codes are also discussed.
Tuesday, June 2nd, 2026
Program Minicourse: Miles Stoudenmire
Time: 11:15 AM - 12:15 PM
Location: SCGP 313
Title: Part 1: Quantum Dynamics in 2D and 3D Using Tensor Belief Propagation
Speaker: Miles Stoudenmire
Abstract: This mini-course will introduce new methods for quantum dynamics simulations based on tensor networks. Until recently, tensor network simulations of dynamics have been primarily limited to one-dimensional systems and short times. However, recent algorithmic developments are rapidly changing this picture. The first family of algorithms discussed will be the belief propagation (BP) framework. BP is well-established in the classical statistical mechanics and spin glass fields, but was only recently adapted for quantum tensor network states. Building on the notion of "tree-like" structure, BP gives offers an affordable and complementary perspective for evolving 2D and even 3D wave functions in real and imaginary time. I will end by discussing recent applications to dynamics and thermal properties of spin systems. The second family of algorithms revolves around the energy content of quantum states. Imaginary time evolution is known to be efficient for tensor networks, due to the rapid damping of high-energy states. One can leverage these benefits for real-time evolution by introducing "complex time" dynamics, which balance benefits of imaginary and real time, in particular controlling the growth of entanglement. Despite the dynamics being fictitious, there are controlled reconstruction techniques to extract real-time correlation functions. I will discuss the philosophy and promise of these methods and possible implications for the future of dynamics simulations.
Title: Part 1: Quantum Dynamics in 2D and 3D Using Tensor Belief Propagation
Speaker: Miles Stoudenmire
Abstract: This mini-course will introduce new methods for quantum dynamics simulations based on tensor networks. Until recently, tensor network simulations of dynamics have been primarily limited to one-dimensional systems and short times. However, recent algorithmic developments are rapidly changing this picture. The first family of algorithms discussed will be the belief propagation (BP) framework. BP is well-established in the classical statistical mechanics and spin glass fields, but was only recently adapted for quantum tensor network states. Building on the notion of "tree-like" structure, BP gives offers an affordable and complementary perspective for evolving 2D and even 3D wave functions in real and imaginary time. I will end by discussing recent applications to dynamics and thermal properties of spin systems. The second family of algorithms revolves around the energy content of quantum states. Imaginary time evolution is known to be efficient for tensor networks, due to the rapid damping of high-energy states. One can leverage these benefits for real-time evolution by introducing "complex time" dynamics, which balance benefits of imaginary and real time, in particular controlling the growth of entanglement. Despite the dynamics being fictitious, there are controlled reconstruction techniques to extract real-time correlation functions. I will discuss the philosophy and promise of these methods and possible implications for the future of dynamics simulations.
Program Minicourse: Miles Stoudenmire
Time: 2:00 PM - 3:00 PM
Location: SCGP 313
Title: Part 2: New Approaches for Quantum Dynamics: Complex and Imaginary Time
Speaker: Miles Stoudenmire
Abstract: This mini-course will introduce new methods for quantum dynamics simulations based on tensor networks. Until recently, tensor network simulations of dynamics have been primarily limited to one-dimensional systems and short times. However, recent algorithmic developments are rapidly changing this picture. The first family of algorithms discussed will be the belief propagation (BP) framework. BP is well-established in the classical statistical mechanics and spin glass fields, but was only recently adapted for quantum tensor network states. Building on the notion of "tree-like" structure, BP gives offers an affordable and complementary perspective for evolving 2D and even 3D wave functions in real and imaginary time. I will end by discussing recent applications to dynamics and thermal properties of spin systems. The second family of algorithms revolves around the energy content of quantum states. Imaginary time evolution is known to be efficient for tensor networks, due to the rapid damping of high-energy states. One can leverage these benefits for real-time evolution by introducing "complex time" dynamics, which balance benefits of imaginary and real time, in particular controlling the growth of entanglement. Despite the dynamics being fictitious, there are controlled reconstruction techniques to extract real-time correlation functions. I will discuss the philosophy and promise of these methods and possible implications for the future of dynamics simulations.
Title: Part 2: New Approaches for Quantum Dynamics: Complex and Imaginary Time
Speaker: Miles Stoudenmire
Abstract: This mini-course will introduce new methods for quantum dynamics simulations based on tensor networks. Until recently, tensor network simulations of dynamics have been primarily limited to one-dimensional systems and short times. However, recent algorithmic developments are rapidly changing this picture. The first family of algorithms discussed will be the belief propagation (BP) framework. BP is well-established in the classical statistical mechanics and spin glass fields, but was only recently adapted for quantum tensor network states. Building on the notion of "tree-like" structure, BP gives offers an affordable and complementary perspective for evolving 2D and even 3D wave functions in real and imaginary time. I will end by discussing recent applications to dynamics and thermal properties of spin systems. The second family of algorithms revolves around the energy content of quantum states. Imaginary time evolution is known to be efficient for tensor networks, due to the rapid damping of high-energy states. One can leverage these benefits for real-time evolution by introducing "complex time" dynamics, which balance benefits of imaginary and real time, in particular controlling the growth of entanglement. Despite the dynamics being fictitious, there are controlled reconstruction techniques to extract real-time correlation functions. I will discuss the philosophy and promise of these methods and possible implications for the future of dynamics simulations.
Wednesday, June 3rd, 2026
Program Talk: Anatoly Dymarsky
Time: 11:15 AM - 12:15 PM
Location: SCGP 313
Title: Title: Holographic Krylov complexity
Speaker: Â Anatoly Dymarsky
Abstract: I will discuss how the Krylov space method can be formulated for holographic theories, and how it can help to define a dual holographic description for non-holographic systems.
Title: Title: Holographic Krylov complexity
Speaker: Â Anatoly Dymarsky
Abstract: I will discuss how the Krylov space method can be formulated for holographic theories, and how it can help to define a dual holographic description for non-holographic systems.
Thursday, June 4th, 2026
Program Talk: Mohammad Maghrebi
Time: 11:15 AM - 12:15 PM
Location: SCGP 313
Title: Universal dynamics from dark states
Speaker: Mohammad Maghrebi
Abstract: Open quantum systems can host dark or subradiant states whose decay is highly suppressed. While these states have been extensively studied in the few-excitation regime, their impact on the many-body dynamics remains largely unexplored. In this talk, I introduce a minimal model of a spin chain with correlated dissipation on neighboring sites, featuring a single-particle dark state at zero momentum. I show that the single-particle dark state qualitatively alters the many-body dynamics at long times, and identify its distinct universal behavior. While the zero-momentum mode is dark at the single-particle level, it decays slowly as 1/ log t as it becomes dressed by other modes through a dissipation-induced nonlinearity. I end the talk with an outlook on new possibilities afforded by dark states for realizing exotic dynamics and even strongly correlated quantum states.
Title: Universal dynamics from dark states
Speaker: Mohammad Maghrebi
Abstract: Open quantum systems can host dark or subradiant states whose decay is highly suppressed. While these states have been extensively studied in the few-excitation regime, their impact on the many-body dynamics remains largely unexplored. In this talk, I introduce a minimal model of a spin chain with correlated dissipation on neighboring sites, featuring a single-particle dark state at zero momentum. I show that the single-particle dark state qualitatively alters the many-body dynamics at long times, and identify its distinct universal behavior. While the zero-momentum mode is dark at the single-particle level, it decays slowly as 1/ log t as it becomes dressed by other modes through a dissipation-induced nonlinearity. I end the talk with an outlook on new possibilities afforded by dark states for realizing exotic dynamics and even strongly correlated quantum states.
Friday, June 5th, 2026
Program Talk: Hosho Katsura
Time: 11:15 AM - 12:15 PM
Location: SCGP 313
Title: Integrable SYK-like models
Speaker: Hosho Katsura
Abstract: In this talk, we introduce two disorder-free variants of the Sachdev–Ye–Kitaev (SYK) model, both built from Majorana fermions with all-to-all interactions: (i) the clean Majorana SYK model and (ii) its N=1 supersymmetric extension. Unlike the original disordered SYK model, which is maximally chaotic, these models are integrable, in the sense that their Hamiltonians commute with a quadratic Hamiltonian. This integrability allows us to study the static and dynamical properties of Model (i) with 4-body interactions in detail. We find that the out-of-time-order correlators (OTOCs) exhibit early-time exponential growth, resembling that of the disordered SYK model. We also discuss the effect of dissipation on this 4-body clean SYK model. Time permitting, I will briefly touch on a disorder-free version of the quantum breakdown model with all-to-all interactions.
Title: Integrable SYK-like models
Speaker: Hosho Katsura
Abstract: In this talk, we introduce two disorder-free variants of the Sachdev–Ye–Kitaev (SYK) model, both built from Majorana fermions with all-to-all interactions: (i) the clean Majorana SYK model and (ii) its N=1 supersymmetric extension. Unlike the original disordered SYK model, which is maximally chaotic, these models are integrable, in the sense that their Hamiltonians commute with a quadratic Hamiltonian. This integrability allows us to study the static and dynamical properties of Model (i) with 4-body interactions in detail. We find that the out-of-time-order correlators (OTOCs) exhibit early-time exponential growth, resembling that of the disordered SYK model. We also discuss the effect of dissipation on this 4-body clean SYK model. Time permitting, I will briefly touch on a disorder-free version of the quantum breakdown model with all-to-all interactions.