Bohmian Trajectories for Hamiltonians with Interior-Boundary Conditions

TL;DR

This paper extends Bohmian mechanics to Hamiltonians with interior-boundary conditions, enabling a consistent description of particle creation and annihilation in quantum field theories without ultraviolet divergence.

Contribution

It introduces a Bohmian framework for Hamiltonians with interior-boundary conditions, incorporating stochastic creation and deterministic annihilation of particles.

Findings

Bohmian trajectories can be defined with IBC Hamiltonians.

Particle creation is stochastic, annihilation is deterministic.

The approach aligns with Bell-type quantum field theories.

Abstract

Recently, there has been progress in developing interior-boundary conditions (IBCs) as a technique of avoiding the problem of ultraviolet divergence in non-relativistic quantum field theories while treating space as a continuum and electrons as point particles. An IBC can be expressed in the particle-position representation of a Fock vector $\psi$ as a condition on the values of $\psi$ on the set of collision configurations, and the corresponding Hamiltonian is defined on a domain of vectors satisfying this condition. We describe here how Bohmian mechanics can be extended to this type of Hamiltonian. In fact, part of the development of IBCs was inspired by the Bohmian picture. Particle creation and annihilation correspond to jumps in configuration space; the annihilation is deterministic and occurs when two particles (of the appropriate species) meet, whereas the creation is stochastic and occurs at a rate dictated by the demand for the equivariance of the $|\psi|^2$ distribution, time reversal symmetry, and the Markov property. The process is closely related to processes known as Bell-type quantum field theories.