Supersymmetry and Strong Dynamics on the Lattice

Investigators:

Simon Catterall (Syracuse University)
Joel Giedt (RPI)

Other co-investigators:

Joe Schneible (Syracuse)
Toby Wiseman (Imperial College)
Francesco Sannino (University of Southern Denmark)

Time awarded: 500,000
Resources: kaon (Fermilab)

Abstract:
We propose a series of projects whose aim is to elucidate the phase structure and dynamics of a variety of lattice gauge theories which may play a role in theories of physics which go beyond the Standard Model. These include supersymmetric theories and models containing massless fermions in exotic representations of the gauge group. Much of the proposed work is an extension of earlier work, both theoretical and numerical, in these areas. Specific topics include the vacuum structure and spectrum of ${\cal N}=1$ super Yang-Mills theory, quenched studies of super QCD, investigations of ${\cal N}=4$ super Yang-Mills theory and its dimensional reductions and a detailed examination of a two color gauge theory co ntaining 2 Dirac flavors of massless adjoint fermions whose dynamics is conjectured to be close to conformal. We request $480,000$ 6n equivalent hours on PC clusters for this work.
Full proposal
Previous years proposal

Subproject status

Date: January 5 2009

Study of N=4 SYM using a supersymmetric lattice action

Parallel code development almost complete (based on MDP libraries) with student Joe Schnieble. Expect running January 2009.
Extend simulations to lattices $4^3\times 8$ and $8^4$. Investigate deconfinement phase transition. Compare numerical results for supersymmetric Wilson loops with theory.

Finite temperature SYM and holography

Simulations of Q=16 SYMQM complete. Good agreement with theory for intermediate and high temperatures. Instability observed at low temperature. Interpreted in terms of Hawking radiation (Phys.Rev.D78:041502,2008).
In progress: regulate IR divergence using scalar mass term. This should allow more explicit contact to be made with black hole predictions. Should be completed during next 6 months.
Extend to two and three dimensional theories - work in progress.

N=1 SYM.

First generation DWF simulations complete arXiv:0810.5746 (accepted for publication PRD). Condensate, string tension measured. Extrapolations to chiral limit performed.
Analysis of disconnected diagrams necessary for spectrum underway. Also, improvement of DWF algorithm (eg moebius fermions). Needed to counter large observed residual mass.

Quenched SQCD

First attempts at this expected this Spring.

Conformal phase in SU(2) with adjoint quarks ?

Survey of phase diagram completed on 8^3x16 lattices. JHEP0811:009,2008.
Current simulations focused on critical endpoint using 16^3x32 lattices.
Simulations with fundamentals in progress to help calibrate the adjoint runs and look for the conformal window.
MDP code development complete. Complements existing code for BG/L based on hack of CPS.

Used approximately 18% allocation at this point.