Replica expressions in the grand canonical ensemble

For a fluid coupled to a reserv oir with chemical potential n, the thermal average at a given matrix realization (and fixed number of matrix particles) is given [instead of the canonical expression EJq. (7.6)] by 

All rulatioiis given in Seetion 7.4 between correlations in the disordered and replicated system, respectively, remain unchanged. Finally, we consider the grand canonical potential, fi, of the adsorbed fluid. Proceeding exactly as for the free energy in the canonical cn mble (see Section 7.6), one finds the analogous expression 

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