Quantum Spin Liquids

Research over the last three decades shows that several low
temperature phases of matter cannot be characterized within the
paradigm of spontaneous symmetry breaking. Hence, a much wider
structure of understanding and classifying phases is being currently
pursued. Studies in frustrated magnets have provided examples of such
unconventional phases and indicated plausible material candidates
where such phases may be realized. These are systems of interacting
spins, that fail to develop magnetic or other orders at low
temperature and yet remain highly correlated.  In this talk, I shall
discuss such phases, dubbed as quantum spin liquids, and show that
they have rich low energy properties that are very different from
those of the ordered phases; recent developments in our understanding
of quantum spin liquids; and, some experimental signatures in context
of concrete material candidates.