English

Unitarity and Universality in non relativistic Conformal Field theory

High Energy Physics - Theory 2019-04-12 v4 Quantum Gases Strongly Correlated Electrons High Energy Physics - Phenomenology

Abstract

We relate the notion of unitarity of a SL(2,R)SL(2,\mathbf{R}) invariant field theory with that of a Schrodinger field theory using the fact that SL(2,R)SL(2,\mathbf{R}) is a subgroup of Schrodinger group. Exploiting SL(2,R)SL(2,\mathbf{R}) unitarity, we derive the unitarity bounds and null conditions for a Schr\"odinger field theory (for the neutral as well as the charged sector). In non integer dimensions the theory is shown to be non-unitary. Furthermore, the use of SL(2,R)SL(2,\mathbf{R}) subgroup opens up the possibility of borrowing results from 1D SL(2,R)SL(2,\mathbf{R}) invariant field theory to explore Schrodinger field theory, in particular, the sector with zero charge. We explore the consequences of SL(2,R)SL(2,\mathbf{R}) symmetry e.g. the convergence of operator product expansion in the kinematic limit, where all the operators (neutral and/or charged) are on same temporal slice (x=constantx=constant), the universal behavior of weighted spectral density function, existence of infinite number of SL(2,R)SL(2,\mathbf{R}) primaries, the analytic behavior of three point function as a function of spatial separation. We discuss the implication of imposing parity invariance (ττ\tau\to-\tau) in addition to Schrodinger invariance and emphasize its difference from time reversal (ττ\tau \to-\tau with charge conjugation).

Keywords

Cite

@article{arxiv.1802.02262,
  title  = {Unitarity and Universality in non relativistic Conformal Field theory},
  author = {Sridip Pal},
  journal= {arXiv preprint arXiv:1802.02262},
  year   = {2019}
}

Comments

12 Pages (two column), 5 Figures v2: added section on subtleties with crossing symmetry v3: ref. added, appendix C removed, app. B extended with discussion of time ordering, typos fixed, discussion of parity mended, v4: Reformatted paper, matches with the published version (except appendix E)