Formal Description of Measurements in Local Quantum Field Theory

1970/01/15 by K. -E. Hellwig, K. Kraus · 1 voice · 3 citations
Computer Science · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Quantum Information and Cryptography #Quantum Mechanics and Applications

paper · doi:10.1103/physrevd.1.566

openalex publication_date 1970/01/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

Ideal measurements in quantum mechanics can be described formally as instantaneous changes of the state vector or, more generally, of the density matrix W. By its lack of covariance, this formalism is not very adequate for relativistic quantum theories such as local field theory. For the latter, we propose a modified formalism, according to which a field measurement in a space-time region C changes the field state W in the future and side cone of C. This proposal is justified by physical considerations.

Cited by

• Wavefunctions and Minkowski Space-Time: On the Reconciliation of Quantum Theory with Special Relativity
• Phenomenological constraints on "impossible" measurements
• State updates and useful qubits in relativistic quantum information

Discussions

• There is a beautiful paper by Hellwig and Kraus K.E. Hellwig and K.Kraus, Formal Description of Measurements in Local Quantum Field Theory PHYSICAL REVlEW D VOLUME 1, NUMBER 2 15 JANUARY 1970 where th [stackexchange, 5 points]

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