Gauge-potential approach to the kinematics of a moving car

A kinematics of the motion of a car is reformulated in terms of the theory of gauge potentials (connection on principal bundle). E(2)-connection originates in the no-slipping contact of the car with a road.Comment: 13 pages, AmsTe

Bounds on Operator Dimensions in 2D Conformal Field Theories

We extend the work of Hellerman (arxiv:0902.2790) to derive an upper bound on the conformal dimension $\Delta_2$ of the next-to-lowest nontrival primary operator in unitary two-dimensional conformal field theories without chiral primary operators. The bound we find is of the same form as found for $\Delta_1$: $\Delta_2 \leq c_{tot}/12 + O(1)$. We find a similar bound on the conformal dimension $\Delta_3$, and present a method for deriving bounds on $\Delta_n$ for any $n$, under slightly modified assumptions. For asymptotically large $c_{tot}$ and fixed $n$, we show that $\Delta_n \leq \frac{c_{tot}}{12}+O(1)$. We conclude with a brief discussion of the gravitational implications of these results.Comment: Corrected typos; revised arguments (adding detail) for clarity, results unchange

A counterexample to the a-'theorem'

The conclusion of the original paper was wrong, due to the incorrect assumption that the low-energy limit at the strongly-coupled point consists of a single, coupled SCFT. By taking into account the fact that the low-energy limit consists of multiple decoupled parts, it was later shown in arXiv:1011.4568 that there is no violation of the a-theorem in this system. Furthermore, the a-theorem itself was convincingly demonstrated in arXiv:1107.3987, and the argument presented there has been further refined. The rest of this paper is kept as it was, for some parts of the discussions might still be of interest. Original abstract: We exhibit a renormalization group flow for a four-dimensional gauge theory along which the conformal central charge 'a' increases. The flow connects the maximally superconformal point of an N=2 gauge theory with gauge group SU(N+1) and N_f=2N flavors in the ultraviolet, to a strongly-coupled superconformal point of the SU(N) gauge theory with N_f=2N massless flavors in the infrared. Our example does not contradict the proof of the a-theorem via a-maximization, due to the presence of accidental symmetries in the infrared limit. Nor does it contradict the holographic a-theorem, because these gauge theories do not possess weakly-curved holographic duals.Comment: 22 pages, 4 figures. v3: The conclusion in the previous version was superseded. Please refer to the abstract for the detail

A Generalized Montgomery Phase Formula for Rotating Self Deforming Bodies

We study the motion of self deforming bodies with non zero angular momentum when the changing shape is known as a function of time. The conserved angular momentum with respect to the center of mass, when seen from a rotating frame, describes a curve on a sphere as it happens for the rigid body motion, though obeying a more complicated non-autonomous equation. We observe that if, after time $\Delta T$, this curve is simple and closed, the deforming body \'{}s orientation in space is fully characterized by an angle or phase $\theta_{M}$. We also give a reconstruction formula for this angle which generalizes R. Montgomery\'{}s well known formula for the rigid body phase. Finally, we apply these techniques to obtain analytical results on the motion of deforming bodies in some concrete examples.Comment: 20 page

Skyrmions and Hall Transport

We derive a generalized set of Ward identities that captures the effects of topological charge on Hall transport. The Ward identities follow from the 2+1 dimensional momentum algebra, which includes a central extension proportional to the topological charge density. In the presence of topological objects like Skyrmions, we observe that the central term leads to a direct relation between the thermal Hall conductivity and the topological charge density. We extend this relation to incorporate the effects of a magnetic field and an electric current. The topological charge density produces a distinct signature in the electric Hall conductivity, which is identified in existing experimental data, and yields further novel predictions. For insulating materials with translation invariance, the Hall viscosity can be directly determined from the Skyrmion density and the thermal Hall conductivity to be measured as a function of momentum.Comment: 6+1 pages including Supplemental Material. Version to appear in Physical Review Letter

Minimal Uncertainty in Momentum: The Effects of IR Gravity on Quantum Mechanics

The effects of the IR aspects of gravity on quantum mechanics is investigated. At large distances where due to gravity the space-time is curved, there appears nonzero minimal uncertainty $\Delta p_{0}$ in the momentum of a quantum mechanical particle. We apply the minimal uncertainty momentum to some quantum mechanical interferometry examples and show that the phase shift depends on the area surrounded by the path of the test particle . We also put some limits on the related parameters. This prediction may be tested through future experiments. The assumption of minimal uncertainty in momentum can also explain the anomalous excess of the mass of the Cooper pair in a rotating thin superconductor ring.Comment: 8 pages, revised version accepted by PR