Skip to content
DraconiticResearch
Search Sources API
201,683 studies31 sourcesUpdated 35 min ago
Peer-reviewedCC BY 4.0Quantum

Towards local and compositional measurements in quantum field theory

  • Robert Oeckl1,2
  • Adamantia Zampeli3
  1. 1Institute for Quantum Optics and Quantum Information, Boltzmanngasse 3, 1090 Vienna, Austria
  2. 2Centro de Ciencias Matemáticas, Universidad Nacional Autónoma de México, C.P. 58190, Morelia, Michoacán, Mexico
  3. 3International Center for Theory of Quantum Technologies, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
Open at sourcePDFDOICite

Abstract

A universal framework for the joint measurement of multiple localized observables in quantum field theory satisfying spacetime locality and compositionality is still lacking. We present an approach to the problem that is based on the one hand on the positive formalism, an axiomatic framework, where it is clear from the outset that we satisfy locality and compositionality, while also having a consistent probabilistic interpretation. On the other hand, the approach is based on standard tools from quantum field theory, in particular the path integral and the Schwinger-Keldysh formalism. After an overview of the conceptual foundations we introduce the modulus-square construction as a formalization of the measurement process for the expectation value of an important class of observables including quadratic observables. We show that this construction has many of the desired properties, including positivity, locality, single measurement recovery and compositionality. We introduce a renormalization scheme for the measurement of quadratic observables that also satisfies compositionality, in contrast to previous renormalization schemes. We discuss relativistic causality, confirming that measurements in our scheme are indeed localized in the spacetime regions where the underlying observables have support.

Related

  1. On recent measurements of toponium threshold enhancement in entire-function-regulated nonlocal quantum field theory
    Ellis Thompson
    The European Physical Journal CPeer-reviewedCC BYFull text8 citedHigh-energy & particle physicsOpenAlex
  2. Detection times are not local observables in quantum field theory
    Charis Anastopoulos, Ntina Savvidou
    arXivPreprintCC BY 4.0Full textMathematical physicsGravitation & general relativityarXiv
  3. On the Meaning of Localization in Non-Local Quantum Field Theory
    E. J. Thompson
    arXivPreprintCC BY 4.0Full textGeneral physicsarXiv
  4. Entanglement of excited states after measurements in conformal field theory
    Hui-Huang Chen
    arXivPreprintCC BY 4.0Full textHigh-energy & particle physicsStatistical & nonlinear physicsarXiv
  5. Adaptive Local Measurements For Quantum Learning Can Exponentially Outperform Nonadaptive Global Measurements
    Alireza Goldar, Zhen Qin, Zhihui Zhu +2
    arXivPreprintarXiv licenceFull textGeneral mathematicsQuantum physics & quantum informationarXiv

Cite

BibTeXRIS
BibTeX
@article{oeckl2026towards,
  title = {{Towards local and compositional measurements in quantum field theory}},
  author = {Robert Oeckl and Adamantia Zampeli},
  journal = {Quantum},
  year = {2026},
  month = oct,
  doi = {10.22331/q-2026-10-08-2232},
  url = {https://quantum-journal.org/papers/q-2026-10-08-2232/},
  note = {CC BY 4.0},
}
RIS
TY  - JOUR
TI  - Towards local and compositional measurements in quantum field theory
AU  - Robert Oeckl
AU  - Adamantia Zampeli
PY  - 2026
DA  - 2026/10/08
JO  - Quantum
DO  - 10.22331/q-2026-10-08-2232
UR  - https://quantum-journal.org/papers/q-2026-10-08-2232/
AB  - A universal framework for the joint measurement of multiple localized observables in quantum field theory satisfying spacetime locality and compositionality is still lacking. We present an approach to the problem that is based on the one hand on the positive formalism, an axiomatic framework, where it is clear from the outset that we satisfy locality and compositionality, while also having a consistent probabilistic interpretation. On the other hand, the approach is based on standard tools from quantum field theory, in particular the path integral and the Schwinger-Keldysh formalism. After an overview of the conceptual foundations we introduce the modulus-square construction as a formalization of the measurement process for the expectation value of an important class of observables including quadratic observables. We show that this construction has many of the desired properties, including positivity, locality, single measurement recovery and compositionality. We introduce a renormalization scheme for the measurement of quadratic observables that also satisfies compositionality, in contrast to previous renormalization schemes. We discuss relativistic causality, confirming that measurements in our scheme are indeed localized in the spacetime regions where the underlying observables have support.
SN  - 2521-327X
ER  -