# On the (im)possibility of extending the GRW model to relativistic particles

## TL;DR

This paper examines the challenges of extending the GRW spontaneous collapse model to relativistic particles, showing it is feasible for single particles or distinguishable non-entangled particles but not in general.

## Contribution

It introduces a relativistic condition for the GRW model and demonstrates its limitations in extending to complex many-particle systems.

## Key findings

- Relativistic GRW model is possible for single particles.
- Relativistic GRW model can be extended to distinguishable non-entangled particles.
- It is impossible to extend the relativistic GRW model to entangled or interacting particles.

## Abstract

Spontaneous collapse models are proposed modifications to quantum mechanics which aim to solve the measurement problem. In this article we will consider models which attempt to extend a specific spontaneous collapse model, the Ghirardi-Rimini-Weber model (GRW), to be consistent with special relativity. We will present a condition that a relativistic GRW model must meet for three cases: for single particle, for N distinguishable particles, and for indistinguishable particles. We will then show that this relativistic condition implies that one can have a relativistic GRW model for a single particle or for distinguishable non-interacting, non-entangled particles but not otherwise.