General Hamiltonian description of nonreciprocal interactions

Date

Nov 11, 2025

Time

10:00 AM - 11:00 AM

Speaker

Dr. Yubo Shi

Affiliation

Max Planck Institute for the Physics of Complex Systems (MPI PKS) Dresden

Language

en

Main Topic

Materialien

Host

Grit Rötzer

Description

In a vast class of systems, which includes members as diverse as active colloids and bird flocks, interactions do not stem from a potential, and are in general nonreciprocal. Thus, it is not possible to define a conventional energy function, nor to use analytical or numerical tools that rely on it. Here, we overcome these limitations by constructing a Hamiltonian that includes auxiliary degrees of freedom; when subject to a constraint, this Hamiltonian yields the original non-reciprocal dynamics. We show that Glauber dynamics based on the constrained Hamiltonian reproduces the steady states of the original Langevin dynamics, as we explicitly illustrate for dissipative XY spins with vision-cone interactions. Further, the symplectic structure inherent to our construction allows us to apply the well-developed notions of Hamiltonian engineering, which we demonstrate by varying the amplitude of a periodic drive to tune the spin interactions between those of a square and a chain lattice geometry. Overall, our framework for generic nonreciprocal pairwise interactions paves the way for bringing to bear the full conceptual and methodological power of conventional statistical mechanics and Hamiltonian dynamics to nonreciprocal systems. .

Links

• Seminars at the IFW

Last modified: Nov 7, 2025, 7:40:01 AM