What is a particle?
Por:
Colosi D., Rovelli C.
Publicada:
21 ene 2009
Categoría:
Physics and Astronomy (miscellaneous)
Resumen:
Theoretical developments related to gravitational interaction have questioned the notion of particle in quantum field theory (QFT). For instance, uniquely defined particle states do not exist in general, in QFT on a curved spacetime. More generally, particle states are difficult to define in a background-independent quantum theory of gravity. These difficulties have led some to suggest that in general QFT should not be interpreted in terms of particle states, but rather in terms of eigenstates of local operators. Still, it is not obvious how to reconcile this view with the empirically-observed ubiquitous particle-like behavior of quantum fields, apparent for instance in experimental high-energy physics, or 'particle' physics. Here we offer an element of clarification by observing that already in flat space there exist-strictly speaking-two distinct notions of particles: globally defined n-particle Fock-states and local particle states. The last describes the physical objects detected b
Filiaciones:
Colosi D.:
Univ Nacl Autonoma Mexico, Inst Matemat, Morelia 58190, Michoacan, Mexico
Rovelli C.:
Centre de Physique Théorique de Luminy, Case 907, F-13288 Marseille, EU, France
All Open Access; Green
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