# Seminars & Colloquia Calendar

Mathematical Physics Seminar

## John Cardy - On the peculiar elastic properties of TTbarite

#### John Cardy - University of California, Berkeley and All Souls College, Oxford

Location:  zoom
Date & time: Wednesday, 27 January 2021 at 10:45AM - 11:45AM

#### John Cardy, University of California, Berkeley and All Souls College, Oxford

Wednesday, January 27, 10:45AM

Title:

"On the peculiar elastic properties of TTbarite"

Abstract:

We argue that the so-called TTbar deformation of two-dimensional field theory, first introduced by Zamolodchikov, is most readily interpreted in the context of 19th century elasticity theory and fluid mechanics. TTbarite'' is a putative magnetoelastic material whose macroscopic properties are described by this deformation. The particular elastic coupling corresponding to the solvable case corresponds to infinite Poisson's ratio, endowing the material with some unusual properties. However this realization suggests that the appropriate framing of the problem is in the fixed stress ensemble, rather than the usual approach which corresponds to fixed strain. The evolution equations are then formally those of a non-interacting two-dimensional fluid. Singularities of the deformed partition function correspond either to collapse of the elastic sample, or to the formation of shock  waves in the fluid.    As examples we compute the TTbar deformed partition functions in a disk and a rectangle, and show that they exhibit singular behavior even in finite volume.

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