Generalized Color Codes Supporting Non-Abelian Anyons

We propose a generalization of the color codes based on finite groups $G$. For non-abelian groups, the resulting model supports non-abelian anyonic quasiparticles and topological order. We examine the properties of these models such as their relationship to Kitaev quantum double models, quasiparticle spectrum, and boundary structure.Comment: 17 pages, 8 figures; references added, typos remove

More than Just Collateral Damage: Pet Shootings by Police

The Department of Justice estimates that American police officers shoot 10,000 pet dogs in the line of duty each year. It is impossible to ascertain a reliable number, however, because most law enforcement agencies do not maintain accurate records of animal killings. The tally may be substantially higher, and some suggest it could reach six figures. Deferring to officers’ judgment when they reasonably fear for human safety is sound policy because they regularly must make split-second, life-or-death decisions in highly stressful situations; but many pet shootings occur when officers mistake the behavior of a friendly, curious dog for aggression. Further, some animals have been deliberately shot and killed under questionable circumstances, including through doors or while tied, running away, or hiding. Studies show that some officers shoot pets unnecessarily, recklessly, or in retaliation, and that subsequent civilian complaints are investigated inadequately. Moreover, not every animal that police officers shoot is a large dog that may be more likely to pose a genuine risk to human safety—or even a dog at all. Police claiming a threat to human safety have shot puppies, Chihuahuas, Miniature Dachshunds, and domestic cats, among other pets. In some tragic cases, bullets missed their nonhuman targets and injured or even killed human bystanders instead. Pet shootings can seriously damage public relations for law enforcement agencies, especially during an era when the news seems to be saturated with stories concerning police using excessive force against unarmed civilians. The American Civil Liberties Union even classifies pet shootings as one symptom of the increased militarization of American police forces. Additionally, lawsuits brought by bereaved owners can cost agencies and taxpayers hundreds of thousands of dollars. This Article explores these and other related issues, and presents simple solutions to help reduce the number of companion animal shootings by police in the United States

Generalized Cluster States Based on Finite Groups

We define generalized cluster states based on finite group algebras in analogy to the generalization of the toric code to the Kitaev quantum double models. We do this by showing a general correspondence between systems with CSS structure and finite group algebras, and applying this to the cluster states to derive their generalization. We then investigate properties of these states including their PEPS representations, global symmetries, and relationship to the Kitaev quantum double models. We also discuss possible applications of these states.Comment: 23 pages, 4 figure

Perturbative 2-body Parent Hamiltonians for Projected Entangled Pair States

We construct parent Hamiltonians involving only local 2-body interactions for a broad class of Projected Entangled Pair States (PEPS). Making use of perturbation gadget techniques, we define a perturbative Hamiltonian acting on the virtual PEPS space with a finite order low energy effective Hamiltonian that is a gapped, frustration-free parent Hamiltonian for an encoded version of a desired PEPS. For topologically ordered PEPS, the ground space of the low energy effective Hamiltonian is shown to be in the same phase as the desired state to all orders of perturbation theory. An encoded parent Hamiltonian for the double semion string net ground state is explicitly constructed as a concrete example.Comment: 26 pages, 4 figures, v2 published versio

Phonological Priming In Young Children Who Stutter: Holistic Versus Incremental Processing

Purpose: To investigate the holistic versus incremental phonological encoding processes of young children who stutter (CWS; N = 26) and age- and gender-matched children who do not stutter (CWNS; N = 26) via a picture-naming auditory priming paradigm. Method: Children named pictures during 3 auditory priming conditions: neutral, holistic, and incremental. Speech reaction time (SRT) was measured from the onset of picture presentation to the onset of participant response. Results: CWNS shifted from being significantly faster in the holistic priming condition to being significantly faster in the incremental priming condition from 3 to 5 years of age. In contrast, the majority of 3- and 5-year-old CWS continued to exhibit faster SRT in the holistic than the incremental condition. Conclusion: CWS are delayed in making the developmental shift in phonological encoding from holistic to incremental processing, a delay that may contribute to their difficulties establishing fluent speech.Communication Sciences and Disorder

A proposal for self-correcting stabilizer quantum memories in 3 dimensions (or slightly less)

We propose a family of local CSS stabilizer codes as possible candidates for self-correcting quantum memories in 3D. The construction is inspired by the classical Ising model on a Sierpinski carpet fractal, which acts as a classical self-correcting memory. Our models are naturally defined on fractal subsets of a 4D hypercubic lattice with Hausdorff dimension less than 3. Though this does not imply that these models can be realised with local interactions in 3D Euclidean space, we also discuss this possibility. The X and Z sectors of the code are dual to one another, and we show that there exists a finite temperature phase transition associated with each of these sectors, providing evidence that the system may robustly store quantum information at finite temperature.Comment: 16 pages, 6 figures. In v2, erroneous argument about embeddability into R3 was removed. In v3, minor changes to match journal versio