Condensed Matter Seminar

Crystallographic defects are always present in solid state materials. Their impact on the fluctuating spin states of magnetic insulators can be significant but is not well understood.  I will present our recent results showing two interesting effects of lattice defects on spin systems. In the triangular lattice magnet KCSO, magneto-transmission measurements of the 1/3 magnetization plateau and spin supersolid phases found unusual satellite lines. We show that though these lines are sharp, they arise from disorder and enable its detailed characterization, here as dilute vacancies.

Abstract: For decades, scientists have pursued a bold goal: creating a laser that works not just with visible light but with powerful X-rays. Conventional X-ray sources, essential in medicine, security, and technology, are based on principles dating back to Röntgen’s discovery in 1895, essentially a brighter, more advanced X-ray light bulb. But just as lasers revolutionized the way we harness visible light, an X-ray laser would unlock extraordinary new capabilities in science and technology. The challenge?

Abstract:  We develop a theory of measurement-induced phase transitions (MIPT) for d-dimensional lattice free fermions subject to random projective measurements of local site occupation numbers. Our analytical approach is based on the Keldysh path-integral formalism and replica trick. In the limit of rare measurements, \gamma << J (where \gamma is measurement rate per site and J is hopping constant), we derive a non-linear sigma model (NLSM) as an effective field theory of the problem.

On Thursday at noon (i.e. the timeslot of the condensed matter seminar) we will have a zoominar from Barislav Buca. Title and abstract are below, as is the zoom link. Please join if you are interested. Best, Rahul

Title: Eigenoperator thermalization theory

Abstract: Quantum computers, machines that harness the power of quantum physics and have the potential to outperform their classical counterparts, have recently captured the public's imagination. Amidst the waves of hype and skepticism in the media, what is at the origin of the excitement and what is the real progress of this quest at the frontiers of quantum science and engineering?

Abstract:

Abstract: One of the most intriguing outcomes of casting our thinking about the world around us in mathematical terms is that phenomena that were thought to be quite distinct are instead revealed as being the “same.” Thinkers as long ago as Pliny the Elder made observations on active matter noting: "It is a peculiarity of the starling to fly in troops, as it were, and then to wheel round in a globular mass like a ball, the central troop acting as a pivot for the rest.’’ In this talk I will introduce field theory and the emergence of the modern theory of active matter as for

Please note time and location difference for this talk.