From a seminar, I heard that energy-momentum relation (E^2=m^2+p^2) is

modified by UV/IR mxing.

In other words, the speaker claimed that the lowest energy is achived

not by zero momentum, but by non-zero momentum. Could somebody refer

me to a relevant paper?

Sorry, I'm not sure I can refer you to immediately relevant papers.

The concept of UV/IR mixing that I've seen came up in the context of

non-commutative field theory. That is, field theory defined on a space-

time where coordinates do not commute. A standard reference for

physicists is a paper by Douglass & Nekrasov [1]. The mathematical

principles of non-commutative spaces are founded in the non-

commutative geometry of Alain Connes [2]. You may find some useful

information in these references.

Hope this helps.

Igor

[1] Douglass & Nekrasov, Noncommutative field theory,

Rev. Mod. Phys. 73, pp.977-1029 (2001)

[2] Connes, Noncommutative Geometry, Academic Press (1994)