@article{discovery1455021, year = {2014}, month = {November}, volume = {108}, number = {3}, journal = {EPL}, title = {Replica symmetry breaking in the Bose glass}, note = {Copyright {\copyright} EPLA, 2014.}, issn = {0295-5075}, author = {Thomson, SJ and Kr{\"u}ger, F}, url = {http://dx.doi.org/10.1209/0295-5075/108/30002}, abstract = {We investigate the nature of the Bose glass phase of the disordered Bose-Hubbard model in d {\ensuremath{>}} 2 and demonstrate the existence of a glass-like replica symmetry breaking (RSB) order parameter in terms of particle number fluctuations. Starting from a strong-coupling expansion around the atomic limit, we study the instability of the Mott insulator towards the formation of a Bose glass. We add some infinitesimal RSB, following the Parisi hierarchical approach in the most general form, and observe its flow under the momentum-shell renormalization group scheme. We find a new fixed point with one-step RSB, corresponding to the transition between the Mott insulator and a Bose glass phase with hitherto unseen RSB. The susceptibility associated to infinitesimal RSB perturbation in the Mott insulator is found to diverge at the transition with an exponent \${$\backslash$}gamma=1/d\$ . Our findings are consistent with the expectation of glassy behavior and the established breakdown of self-averaging. We discuss the possibility of measuring the glass-like order parameter in optical-lattice experiments as well as in certain spin systems that are in the same universality class as the Bose-Hubbard model.} }