Although quantum mechanics was discovered and formulated nearly a century ago, open questions remain concerning its role and scope in condensed matter systems. In such systems, the number of relevant particles can become large, and it is not established how - or to what extent - quantum effects persist. Two different, interesting regimes can emerge depending on the strength of interactions within a condensed matter system.
On one hand, when inter-particle interactions are very pronounced, the involved physics can be strongly correlated, and quantum effects can occur in collective phenomena involving multitudes of particles. One particularly interesting example of strongly correlated physics is the fractional quantum hall effect, which we study in both GaAs/AlGaAs heterostructures and graphene.
On the other hand, when inter-particle interactions are weak, individual particles can be isolated and coherently manipulated. These isolated particles can serve as building blocks (quantum bits) for generating controllable large-scale quantum systems, which are attractive as they allow for quantum information processing and computation, an area of immense research and interest. In the Yacoby lab, we investigate such possibilities in both double quantum dots and in nitrogen-vacancy (NV) centers in diamond.
Additionally, we are examining exciting new systems that span the above two regimes by investigating how quantum bits can be generated and used in strongly correlated materials. In particular, there are a class of two-dimensional systems where strong interactions give rise to excitations whose state is dependent on the system's topology. We are investigating how such topological physics can arise in condensed matter systems and how they may form the basis for fault-tolerant quantum information processing.
Our experiments are motivated not only to understand underlying physics but also to apply established physics to scientific environments. In particular, we have had great success in developing metrology tools based on novel physical phenomena. Using this principle we have built systems capable of extremely sensitive charge detection as well nanoscale magnetic field sensors. These sensors allow us to probe new physics.