Relativistic compatibility of quantum open systems

Establish or refute the conjecture that only classical open systems can be relativistic while quantum open systems necessarily violate Lorentz (relativistic) symmetry, by analyzing system–environment separations and entanglement within the Closed Time Path framework and related open quantum field theories.

Background

The authors argue that the separation between system and environment, essential for open-system descriptions, introduces non-relativistic features in quantum dynamics because entanglement generated during time evolution spoils factorized initial conditions under Lorentz boosts.

They formulate a conjecture that relativistic symmetry can be maintained only for classical open systems, whereas quantum open systems inherently break relativistic invariance. This touches on foundational issues in reconciling openness (environmental coupling) with relativistic symmetry.

References

We conjecture that only classical open system can be relativistic and quantum open systems always violate relativistic symmetry.

— Classical limit of a scalar quantum field theory  (2510.18025 - Nagy et al., 20 Oct 2025) in Section 4, Non-relativistic open systems

What remains open is either to construct a model satisfying covariance, no-signaling, bounded energy increase, and standard degrees of freedom, or to prove a stronger no-go theorem ruling out such models even with state-dependent collapse operators in curved spacetime.

— Demystifying Relativistic Quantum Collapse  (2608.26474 - Muciño et al., 27 Aug 2026) in Section Conclusions

Existing proposals suggest possible ways of combining bounded energy increase, covariance, and an acceptable account of signaling, though it remains unclear how far these strategies can be pushed.

— Demystifying Relativistic Quantum Collapse  (2608.26474 - Muciño et al., 27 Aug 2026) in Section Conclusions

Unfortunately, it is unclear whether their master equation can be derived from a consistent and relativistic state evolution equation.

— Demystifying Relativistic Quantum Collapse  (2608.26474 - Muciño et al., 27 Aug 2026) in Footnote in Section Conclusions