Fractional Quantum Hall Hierarchy and the Second Landau Level

We generalize the fractional quantum Hall hierarchy picture to apply to arbitrary, possibly non-Abelian, fractional quantum Hall states. Applying this to the nu = 5/2 Moore-Read state, we construct new explicit trial wavefunctions to describe the fractional quantum Hall effect in the second Landau level. The resulting hierarchy of states, which reproduces the filling fractions of all observed Hall conductance plateaus in the second Landau level, is characterized by electron pairing in the ground state and an excitation spectrum that includes non-Abelian anyons of the Ising type. We propose this as a unifying picture in which p-wave pairing characterizes the fractional quantum Hall effect in the second Landau level.Comment: 10 pages; v2: many additional details and discussion included to help clarify the original results, including a composite fermion type formulation of some of the states; v3: minor correction

Probing Non-Abelian Statistics with QuasiParticle Interferometry

We examine interferometric experiments in systems that exhibit non-Abelian braiding statistics, expressing outcomes in terms of the modular S-matrix. In particular, this result applies to FQH interferometry, and we give a detailed treatment of the Read-Rezayi states, providing explicit predictions for the recently observed nu=12/5 plateau.Comment: 5 pages, 1 figure; v2: references added, orientation convention of the modular S-matrix changed, clarification regarding particle-hole transformation added; v3: references updated, clarifying changes made to conform to the version published in PR

Interferometric signature of non-Abelian anyons

We consider the tunneling current through a double point-contact Fabry-Pérot interferometer such as used in recent experimental studies of the fractional quantum Hall plateau at filling fraction v=5/2. We compare the predictions of several different models of the state of the electrons at this plateau: the Moore-Read, anti-Pfaffian, SU(2)_2 NAF, K=8 strong pairing, and (3,3,1) states. All of these predict the existence of charge e/4 quasiparticles, but the first three are non-Abelian while the last two are Abelian. We give explicit formulas for the scaling of charge e/2 and charge e/4 quasiparticle contributions to the current as a function of temperature, gate voltage, and distance between the two point contacts for all three models. Based on these, we analyze several possible explanations of two phenomena reported for recent experiments by Willett et al., namely, halving of the period of the observed resistance oscillations with rising temperature and alternation between the same two observed periods at low temperatures as the area of the interference loop is varied with a side gate. We conclude that the most likely explanation is that the observed alternation is due to switching between even and odd numbers of charge e/4 quasiparticles enclosed within the loop as a function of side-gate voltage, which is a clear signature of the presence of non-Abelian anyons. However, there are important features of the data which do not have a simple explanation within this picture. We suggest further experiments which could help rule out some possible scenarios. We make the corresponding predictions for future tunneling and interference experiments at the other observed second Landau level fractional quantum Hall states

Joint multicast routing and channel assignment in multiradio multichannel wireless mesh networks using simulated annealing

This is the post-print version of the article - Copyright @ 2008 Springer-VerlagThis paper proposes a simulated annealing (SA) algorithm based optimization approach to search a minimum-interference multicast tree which satisfies the end-to-end delay constraint and optimizes the usage of the scarce radio network resource in wireless mesh networks. In the proposed SA multicast algorithm, the path-oriented encoding method is adopted and each candidate solution is represented by a tree data structure (i.e., a set of paths). Since we anticipate the multicast trees on which the minimum-interference channel assignment can be produced, a fitness function that returns the total channel conflict is devised. The techniques for controlling the annealing process are well developed. A simple yet effective channel assignment algorithm is proposed to reduce the channel conflict. Simulation results show that the proposed SA based multicast algorithm can produce the multicast trees which have better performance in terms of both the total channel conflict and the tree cost than that of a well known multicast algorithm in wireless mesh networks.This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) of UK under Grant EP/E060722/1

Decoherence of Anyonic Charge in Interferometry Measurements

We examine interferometric measurements of the topological charge of (non-Abelian) anyons. The target's topological charge is measured from its effect on the interference of probe particles sent through the interferometer. We find that superpositions of distinct anyonic charges a and a' in the target decohere (exponentially in the number of probes particles used) when the probes have nontrivial monodromy with the charges that may be fused with a to give a'.Comment: 5 pages, 1 figure; v2: reference added, example added, clarifying changes made to conform to the version published in PR

Short cap technique to complete EMR of very flat colorectal laterally spreading tumors

We demonstrate the utility of a short cap placed over the colonoscope tip to facilitate EMR of very flat portions of laterally spreading tumors (LSTs) (Fig. 1A). Snare resection is preferred over ablative techniques for the removal of very flat portions that resist snaring. Snaring of very flat portions is often frustrating because even a stiff snare may slide over the very flat tissue

Endoscopic recognition of the sessile serrated polyp to cancer sequence

Sessile serrated polyps (SSPs), also called sessile serrated adenomas (SSAs), are the precursor lesions of 20% to 30% of colorectal cancers. The serrated polyp to cancer sequence occurs primarily in the proximal colon in the case of SSPs

Foundation Sign Correction in Stochastic Analysis Procedures

There are “ABS, SRSS, CQC, MSRSS…” methods in stochastic analysis of structures, that are based on the mean of the response squares. One of the most accurate stochastic methods is MSRSS, that is defined as equation (1). E[y2]=∑j=1N Rj2 + 2 ∑k=j+1NRjk The maximum modal responses are positive or singles, and therefore direction of the forces act on the foundation are alike. In these cases foundation analysis is not valid and the force sign correction must be used. In this paper, besides considering the stochastic methods shortly, a method for sign correction based on the time history analysis will be presented

Numerical Evidence for a p_x - ip_y Paired Fractional Quantum Hall State at ν = 12/5

We provide numerical evidence supporting a Bonderson–Slingerland (BS) non-Abelian hierarchy state as a candidate for the observed ν = 12/5 quantum Hall plateau. We confirm the existence of a gapped incompressible ν = 12/5 quantum Hall state with shift S = 2 matching that of the BS state. The exact ground-state of the Coulomb interaction state on the sphere is shown to have large overlap with the BS ground-state trial wavefunction. The analysis of the BS states is extended to hierarchical descendants of general paired states in the weak-pairing phase at ν = 5/2