title: Quantum phase transition in capacitively coupled double quantum dots.
abstract: We investigate two equivalent, capacitively coupled semiconducting quantum dots, each coupled to its own lead, in a regime where there are two electrons on the double dot. With increasing interdot coupling, a rich range of behavior is uncovered: first a crossover from spin- to charge-Kondo physics, via an intermediate SU(4) state with entangled spin and charge degrees of freedom, followed by a quantum phase transition of Kosterlitz-Thouless type to a non-Fermi-liquid "charge-ordered" phase with finite residual entropy and anomalous transport properties. Physical arguments and numerical renormalization group methods are employed to obtain a detailed understanding of the problem.
authors.affiliation: Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Galpin
authors.forename: David E
authors.initials: DE
authors.lastname: Logan
authors.forename: H R
authors.initials: HR
authors.lastname: Krishnamurthy