Ultratunable Quantum Frequency Conversion in Photonic Crystal Fiber.

Quantum frequency conversion of single photons between wavelength bands is a key enabler to realizing widespread quantum networks. We demonstrate the quantum frequency conversion of a heralded 1551 nm photon to any wavelength within an ultrabroad (1226-1408 nm) range in a group-velocity-symmetric photonic crystal fiber, covering over 150 independent frequency bins. The target wavelength is controlled by tuning only a single pump laser wavelength. We find internal, and total, conversion efficiencies of 12(1)% and 1.4(2)%, respectively. For the case of converting 1551 to 1300 nm we measure a heralded g^{(2)}(0)=0.25(6) for converted light from an input with g^{(2)}(0)=0.034(8). We expect that this photonic crystal fiber can be used for myriad quantum networking tasks.

From photons to phonons and back: a THz optical memory in diamond.

Optical quantum memories are vital for the scalability of future quantum technologies, enabling long-distance secure communication and local synchronization of quantum components. We demonstrate a THz-bandwidth memory for light using the optical phonon modes of a room temperature diamond. This large bandwidth makes the memory compatible with down-conversion-type photon sources. We demonstrate that four-wave mixing noise in this system is suppressed by material dispersion. The resulting noise floor is just 7×10(-3) photons per pulse, which establishes that the memory is capable of storing single quanta. We investigate the principle sources of noise in this system and demonstrate that high material dispersion can be used to suppress four-wave mixing noise in Λ-type systems.

Inadequacies and hazards of chymopapain injections as treatment for intervertebral disc disease.

Chymopapain chemonucleolysis was performed on 100 patients with primary lumbar intervertebral disc disease. The results were compared with those of 174 patients who underwent laminotomy, foraminotomy, and discectomy. Primary lumbar intervertebral disc disease was arbitrarily divided into degenerative, complex, previous surgical, and simple disc syndromes. No difference was seen between chemonucleolysis and surgery in the first three divisions; between 55 percent and 60 per cent of patients responded successfully to treatment. In the simple disc division 89 per cent of the surgical and 60 per cent of the chemonucleolysis patients had successful results.

Entangling macroscopic diamonds at room temperature.

Quantum entanglement in the motion of macroscopic solid bodies has implications both for quantum technologies and foundational studies of the boundary between the quantum and classical worlds. Entanglement is usually fragile in room-temperature solids, owing to strong interactions both internally and with the noisy environment. We generated motional entanglement between vibrational states of two spatially separated, millimeter-sized diamonds at room temperature. By measuring strong nonclassical correlations between Raman-scattered photons, we showed that the quantum state of the diamonds has positive concurrence with 98% probability. Our results show that entanglement can persist in the classical context of moving macroscopic solids in ambient conditions.

Multimode memories in atomic ensembles.

The ability to store multiple optical modes in a quantum memory allows for increased efficiency of quantum communication and computation. Here we compute the multimode capacity of a variety of quantum memory protocols based on light storage in ensembles of atoms. We find that adding a controlled inhomogeneous broadening improves this capacity significantly.

Surgical injury of the cord and its roots.

Fifty-two patients sustained spinal cord, nerve root or combined injury following treatment conducted primarily by neurological and orthopaedic surgeons. Most patients did not receive the benefit of appropriate conservative treatment. Correct diagnosis was usually not arrived at even though diagnostic studies were performed sufficiently well to permit such diagnosis. Surgical treatment fell below standard in 86% of the cases in which the issue of adequacy was relevant. Post-operative care was also generally inadequate. The surgeons often failed to detect, diagnose, or reoperate promptly and properly for post-operative paralysis. These adverse results were not related to isolated surgical mishaps, to natural course of the disease, or to the inevitable result of treatment. They stem from a general failure of the surgeon to meet his responsibilities as a practitioner. There are both medical and social implications of this finding.

Proceedings of the Annual Scientific Meeting of the International Medical Society of Paraplegia held at Stoke Mandeville from 28-30 July 1977 (Part II). Fracture dislocation of the cervical spine: a critique of current management in the United States.

The author has been asked to review the hospital records and X-rays of 12 patients from various regions of the United States who have sustained fracture dislocations of the cervical spine. In no instance was the initial care considered to be appropriate. No patient was significantly improved by treatment although only 17% had apparent complete transverse cord syndromes on admission. Sixty-seven per cent of the patients became worse. In the latter group there were three patients who were admitted with either no neurological deficit or only minimal pyramidal signs. All of these three patients became tetraplegic as a consequence of their not being immobilised or placed in traction during periods of many hours to several days after admission. There is little evidence that the treating physicians understood the need for immediate immobilisation, proper examination, steroid therapy, adequate safe radiological examination, expedited traction, postural adjustments, or follow-up examination. After-care was poor, leading to excessive complication. Two patients were transferred in deteriorating condition to other hospitals without safeguards and with adverse result. The availability and the performance of neurological surgeons during the first critical hours after injury was generally suboptimal. Although all of the patients were admitted within an hour of injury only three were seen by a neurosurgeon within 2 hours of admission. Three patients were seen between 36 hours and 8 days. The remaining six patients were examined between 4 and 36 hours and at an average of 12 hours. Skeletal traction was instituted on an average of 11 hours after admission excluding one case of delay for 9 days. Only two patients had adequate reduction within 28 hours. Steroids were given to eight patients at an average of 6 1/2 hours following admission but usually in inadequate dosage. Five laminectomies and six anterior fusions were eventually performed. Two patients had both operations. One patient subsequently expired. No patient had a surgically remedial lesion or showed postoperative favourable change in cord function. Five operated patients developed spine deformity, persistent dislocation, spinal canal stenosis or instability. This care was generally attested to meet proper standards and to represent the treatment ordinarily rendered when academic and qualified neurosurgeons gave testimony regarding it. Neither the funding of care and research, nor the adopted codes governing treatment in accredited hospitals, nor accepted teaching would appear to have influenced the substandard of care provided these patients. Other statistics confirm this to be a prevailing circumstance.

Injection of collagenase in the treatment of herniated lumbar disk. Initial clinical report.

Twenty-nine patients with persistent, low back and sciatic pain received intradiscal collagenase at a single abnormal disk space after two months of conservative therapy and two weeks of additional bed rest. Complete pain relief was achieved in six patients (21%), notable relief in 12 (42%), moderate in six (21%), and slight in one. Four patients (14%) who obtained no improvement by enzyme injection recovered after extruded disk fragments were removed from the spinal canal during a later operation. Pain relief after collagenase injection took place gradually over a two- to three-week period and was associated with some early backache. Improvement then continued at a slower rate for two to three months. There were no adverse effects of enzyme therapy. Injected disk spaces usually showed radiological narrowing.