We describe a method for sensing short range forces using matter wave interference in dielectric nanospheres. When compared with atom interferometers, the larger mass of the nanosphere results in reduced wave packet expansion, enabling investigations of forces nearer to surfaces in a freefall interferometer. By laser cooling a nanosphere to the ground state of an optical potential and releasing it by turning off the optical trap, acceleration sensing at the 10 −8 m/s 2 level is possible. The approach can yield improved sensitivity to Yukawa-type deviations from Newtonian gravity at the 5 µm length scale by a factor of 10 4 over current limits.

Motivated by the appearance of a "reflection symmetry" in transport experiments and the absence of statistical periodicity in relativistic quantum field theories, we propose a series of relativistic composite fermion theories for the compressible states appearing at filling fractions ν = 1/2n in quantum Hall systems. These theories consist of electrically neutral Dirac fermions attached to 2n flux quanta via an emergent Chern-Simons gauge field. While not possessing an explicit particle-hole symmetry, these theories reproduce the known Jain sequence states proximate to ν = 1/2n, and we show that such states can be related by the observed reflection symmetry, at least at mean field level. We further argue that the lowest Landau level limit requires that the Dirac fermions be tuned to criticality, whether or not this symmetry extends to the compressible states themselves.

It is an important open problem to understand the landscape of non-Abelian fractional quantum Hall phases which can be obtained starting from physically motivated theories of Abelian composite particles. We show that progress on this problem can be made using recently proposed non-Abelian bosonization dualities in 2+1 dimensions, which morally relate U (N ) k and SU (k) −N Chern-Simons-matter theories. The advantage of these dualities is that regions of the phase diagram which may be obscure on one side of the duality can be accessed by condensing local operators on the other side. Starting from parent Abelian states, we use this approach to construct Landau-Ginzburg theories of non-Abelian states through a pairing mechanism. In particular, we obtain the bosonic Read-Rezayi sequence at fillings ν = k/(kM + 2) by starting from k layers of bosons at ν = 1/2 with M Abelian fluxes attached. The Read-Rezayi states arise when k-clusters of the dual non-Abelian bosons condense. We extend this construction by showing that N f -component generalizations of the Halperin (2, 2, 1) bosonic states have dual descriptions in terms of SU (N f + 1) 1 Chern-Simons-matter theories, revealing an emergent global symmetry in the process. Clustering k layers of these theories yields a non-Abelian SU (N f )-singlet state at filling ν = kN f /(N f + 1 + kM N f ).ψ ↔ φ These authors contributed equally to the development of this work.Recent progress in the study of non-Abelian Chern-Simons-matter theories in their large-Using the non-Abelian bosonization dualities, we construct LG theories of the full bosonic RR sequence at filling fractions ν = k/(kM + 2), k, M ∈ Z, which do not suffer from these problems. These theories are obtained by starting with k layers of ν = 1/2 bosonic QH

We consider a family of quantum loop models in 2+1 spacetime dimensions with marginally long-ranged and statistical interactions mediated by a U (1) gauge field, both purely in 2+1 dimensions and on a surface in a 3+1 dimensional bulk system. In the absence of fractional spin, these theories have been shown to be self-dual under particle-vortex duality and shifts of the statistical angle of the loops by 2π, which form a subgroup of the modular group, PSL(2, Z). We show that careful consideration of fractional spin in these theories completely breaks their statistical periodicity and describe how this occurs, resolving a disagreement with the conformal field theories they appear to approach at criticality. We show explicitly that incorporation of fractional spin leads to loop model dualities which parallel the recent web of 2+1 dimensional field theory dualities, providing a nontrivial check on its validity.

Metallic phases have been observed in several disordered two dimensional (2d) systems, including thin films near superconductor-insulator transitions and quantum Hall systems near plateau transitions. The existence of 2d metallic phases at zero temperature generally requires an interplay of disorder and interaction effects. Consequently, experimental observations of 2d metallic behavior have largely defied explanation. We formulate a general stability criterion for strongly interacting, massless Dirac fermions against disorder, which describe metallic ground states with vanishing density of states. We show that (2+1)-dimensional quantum electrodynamics (QED3) with a large, even number of fermion flavors remains metallic in the presence of weak scalar potential disorder due to the dynamic screening of disorder by gauge fluctuations. We also show that QED3 with weak mass disorder exhibits a stable, dirty metallic phase in which both interactions and disorder play important roles.