The possibility of Lorentz symmetry breaking (LSB) has attracted considerableattention in recent years. Spontaneous LSB, in particular, offers theattractive prospect of the graviton as a Nambu-Golstone boson. Here we considerthe question of spontaneous LSB in lattice gauge theories via formation offermion condensates in the strong coupling and large N limits. We employ naivemassless fermions in a fermionic hopping expansion in the presence of sourcescoupled to various condensate operators of interest. The expansion is summed inthe large N limit in two equivalent ways: (i) direct summation of all leading Ngraphs; and (ii) construction of the corresponding large N effective action forcomposite operators. When sources are turned off a variety of fermioniccondensates is found to persist. These include the chiral symmetry breakingcondensates, thus recovering previous results, but also some LSB condensates,in particular, axial vector and rank-2 tensor condensates. Furthermore, in thepresence of internal (global) symmetry groups, formation of condensates"locking" internal and external (Lorentz subgroup) symmetries is found to alsobecome possible. Some implications and open questions are briefly discussed.
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