Contributions to single-shot energy exchanges in open quantum systems.

The exchange of energy between a classical open system and its environment can be analyzed for a single run of an experiment using the phase-space trajectory of the system. By contrast, in the quantum regime such energy exchange processes must be defined for an ensemble of runs of the same experiment based on the reduced system density matrix. Single-shot approaches based on stochastic wave functions have been proposed for quantum systems that are continuously monitored or weakly coupled to a heat bath. However, for systems strongly coupled to the environment and not continuously monitored, a single-shot analysis has not been attempted because no system wave function exists for such systems within the standard formulation of quantum theory. Using the notion of the conditional wave function of a quantum system, we derive here an exact formula for the rate of total energy change in an open quantum system, valid for arbitrary coupling between the system and the environment. In particular, this allows us to identify three distinct contributions to the total energy flow: an external contribution coming from the explicit time dependence of the Hamiltonian, an interaction contribution associated with the interaction part of the Hamiltonian, and an entanglement contribution, directly related to the presence of entanglement between the system and its environment. Given the close connection between weak values and the conditional wave function, the approach presented here provides a new avenue for experimental studies of energy fluctuations in open quantum systems.

Perfect Transmission through Disordered Media.

The transmission of a wave through a randomly chosen "pile of plates" typically decreases exponentially with the number of plates, a phenomenon closely related to Anderson localization. In apparent contradiction, we construct disordered planar permittivity profiles which are complex valued (i.e., have reactive and dissipative properties) that appear to vary randomly with position, yet are one-way reflectionless for all angles of incidence and exhibit a transmission coefficient of unity. In addition to these complex-valued "random" planar permittivity profiles, we construct a family of real-valued, two-way reflectionless and perfectly transmitting disordered permittivity profiles that function only for a single angle of incidence and a narrow frequency range.

Observation of Noise Correlated by the Hawking Effect in a Water Tank.

We measured the power spectrum and two-point correlation function for the randomly fluctuating free surface on the downstream side of a stationary flow with a maximum Froude number F_{max}≈0.85 reached above a localized obstacle. On such a flow the scattering of incident long wavelength modes is analogous to that responsible for black hole radiation (the Hawking effect). Our measurements of the noise show a clear correlation between pairs of modes of opposite energies. We also measure the scattering coefficients by applying the same analysis of correlations to waves produced by a wave maker.

Transmutation of singularities and zeros in graded index optical instruments: a methodology for designing practical devices.

We describe a design methodology for modifying the refractive index profile of graded-index optical instruments that incorporate singularities or zeros in their refractive index. The process maintains the device performance whilst resulting in graded profiles that are all-dielectric, do not require materials with unrealistic values, and that are impedance matched to the bounding medium. This is achieved by transmuting the singularities (or zeros) using the formalism of transformation optics, but with an additional boundary condition requiring the gradient of the co-ordinate transformation be continuous. This additional boundary condition ensures that the device is impedance matched to the bounding medium when the spatially varying permittivity and permeability profiles are scaled to realizable values. We demonstrate the method in some detail for an Eaton lens, before describing the profiles for an "invisible disc" and "multipole" lenses.

Foot and ankle infections after surgery.

Infection after foot and ankle surgery or trauma can range from the common superficial cellulitis to the less common deep soft tissue or bone infections that can have disastrous consequences. The emergence of antibiotic-resistant organisms has made treatment of infection more difficult, even though promising new antibiotics are being developed. Prevention of infection, through proper patient selection and meticulous surgical technique, is essential to satisfactory outcomes.

Orthotic and prosthetic devices in partial foot amputations.

With advanced surgical techniques and orthotic, as well as prosthetic devices, partial foot amputations have become a viable alternative. Orthotics can help restore stability, maintain support, and protect function of the residual limb. The authors discuss orthotic and prosthetic management of patients who have undergone toe amputations; ray amputations; transmetatarsal, Lisfranc-, or Chopart-level amputations.

Percutaneous CT guided resection of osteoid osteoma of the tibial plafond.

Osteoid osteomas of the foot and ankle are relatively rare and notoriously difficult to diagnose. Juxta-articular osteoid osteomas are more difficult to treat and often have a significant delay in diagnosis. We report a case of a juxta-articular osteoid osteoma of the tibial plafond. Once the diagnosis was made, excisional biopsy was performed percutaneously under computed tomography (CT) guidance as an outpatient in the radiology suite. The patient had complete resolution of symptoms and remains pain free at two years follow-up. CT guided resection can be a lower morbidity and more cost effective technique to treat this lesion than traditional methods.

Hybrid casts: a comparison of different casting materials.

Casting and splinting materials used in orthopedics have historically consisted of plaster of Paris and, more recently, fiberglass. Plaster is cost-effective and malleable enough to help to hold reductions. Fiberglass is stronger and lighter, but more expensive. The hybrid cast of plaster and fiberglass optimizes the advantages of both materials in fracture management; it is sufficiently strong, yet still cost-effective.