Revealing novel quantum phases in quantum antiferromagnets on random lattices

Quantum magnets represent an ideal playground for the controlled realization of novel quantum phases and of quantum phase transitions. The Hamiltonian of the system can be indeed manipulated by applying a magnetic eld or pressure on the sample. When doping the system with non-magnetic impurities, novel inhomogeneous phases emerge from the interplay between geometric randomness and quantum uctuations. In this paper we review our recent work on quantum phase transitions and novel quantum phases realized in disordered quantum magnets. The system inhomogeneity is found to strongly affect phase transitions by changing their universality class, giving the transition a novel, quantum percolative nature. Such transitions connect conven-tionally ordered phases to unconventional, quantum disordered ones quantum Grifths phases, magnetic Bose glass phases exhibiting gapless spectra associated with low-energy localized excitations