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Wednesday, Feb 5, 2025
No colloquium: Department meeting

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Wednesday, Feb 12, 2025
No colloquium: faculty search meetings

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Wednesday, Feb 19, 2025
No colloquium: faculty search meetings

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Wednesday, Feb 26, 2025
No colloquium: faculty search meetings

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Wednesday, March 5, 2025
Nathan Harshman (American University)

Quantum Abacus: Anyons in One Dimension

The classical abacus is a digital computer that allows computation by manipulating the location of beads. Recent experimental advances with ultracold atoms in one dimensional optical traps motivate considering what a quantum abacus could do. In this talk, I use the possibility of a quantum abacus to explain and explore the ideas of topological quantum computing with anyons. Most proposals for topological quantum computers rely on the properties of braiding anyons in two dimensions. But is it possible to make a topological quantum computer in one dimension? Are anyons even possible in one dimension? The answer, recently confirmed by experiments, is yes: topological exchange statistics are possible in one dimension.

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Wednesday, March 12, 2025
No colloquium: faculty search meetings

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Wednesday, March 19, 2025
No colloquium -- Spring break

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Wednesday, March 26, 2025
Jose P. D’Incao (UMass Boston)

TBA

Abstract

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Wednesday, April 2, 2025
Lode Pollet (LMU Munich)

Quantum Simulation of Many-body physics with Rydberg systems: from supersolids to spin liquids

Rydberg tweezer arrays provide a versatile platform to explore quantum magnets. Different types of interactions, such as dipolar XY,  van-der-Waals Ising  ZZ, and spin-flip terms, can simultaneously exist.

Furthermore, the Rydberg blockade mechanism can be used to prevent the excitation of another, nearby-situated Rydberg atom akin to the Gauss law in lattice gauge theory.

In the talk I give an overview of the current state of the art and report on two different types of physics that can be realized with such platforms.

First, I comment on a recent experiment which exploited the blockade mechanism in order to observe the onset of a dynamically prepared, gapped Z2 quantum spin liquid on the ruby lattice (Semgehini et al, Science 374, 1242 (2021)). The thermodynamic properties of such models remain inadequately addressed, yet knowledge thereof is indispensable if one wants to prepare large, robust, and long-lived quantum spin liquids. Using large scale quantum Monte Carlo simulations we find a renormalized classical spin liquid which better explains part of the experimental observations than a quantum spin liquid. I comment on the adiabatic approximation to the dynamical ramps for the electric degrees of freedom, and the magnitude of the observed string parity order parameters.

Second, through combining the dipolar XY and Ising ZZ interactions, we predict the existence of a robust supersolid phase on the triangular lattice for 100s of particles based on explicitly calculated pair interactions for 87Rb and with a critical entropy in reach of current technology. Such a lattice supersolid is long-lived, found over a wide parameter range in an isotropic and flat two-dimensional geometry. It has true long-range order, even at finite temperature, thanks to the dipolar interactions, and would constitute a rare example of the defect-induced paradigm of supersolidity.

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Wednesday, April 9, 2025
TBA

TBA

Abstract
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Wednesday, April 16, 2025
Rosa González (UNAM)

TBA

Abstract

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Wednesday, April 23, 2025
Tim Atherton (Tufts)

TBA

Abstract

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Wednesday, April 30, 2025
TBA

TBA

Abstract

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Wednesday, May 7, 2025
Reuben Wang (ITAMP/Harvard)

TBA

Abstract

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Wednesday, May 14, 2025
No colloquium -- End of Semester