Biomedical subjects

L Childress

Publications and source records attributed to L Childress.

6 recordsLinked to original sources

PubMed2006

Coherent dynamics of coupled electron and nuclear spin qubits in diamond.

Understanding and controlling the complex environment of solid-state quantum bits is a central challenge in spintronics and quantum information science. Coherent manipulation of an individual electron spin associated with a nitrogen-vacancy center in diamond was used to gain insight into its local environment. We show that this environment is effectively separated into a set of individual proximal 13C nuclear spins, which are coupled coherently to the electron spin, and the remainder of the 13C nuclear spins, which cause the loss of coherence. The proximal nuclear spins can be addressed and coupled individually because of quantum back-action from the electron, which modifies their energy levels and magnetic moments, effectively distinguishing them from the rest of the nuclei. These results open the door to coherent manipulation of individual isolated nuclear spins in a solid-state environment even at room temperature.

Journal Article↗

PubMed2006

Fault-tolerant quantum communication based on solid-state photon emitters.

We describe a novel protocol for a quantum repeater that enables long-distance quantum communication through realistic, lossy photonic channels. Contrary to previous proposals, our protocol incorporates active purification of arbitrary errors at each step of the protocol using only two qubits at each repeater station. Because of these minimal physical requirements, the present protocol can be realized in simple physical systems such as solid-state single photon emitters. As an example, we show how nitrogen-vacancy color centers in diamond can be used to implement the protocol, using the nuclear and electronic spin to form the two qubits.

Journal Article↗

PubMed2004

Shaping quantum pulses of light via coherent atomic memory.

We describe proof-of-principle experiments demonstrating a novel approach for generating pulses of light with controllable photon numbers, propagation direction, timing, and pulse shapes. The approach is based on preparation of an atomic ensemble in a state with a desired number of atomic spin excitations, which is later converted into a photon pulse. Spatiotemporal control over the pulses is obtained by exploiting long-lived coherent memory for photon states and Electromagnetically Induced Transparency in an optically dense atomic medium. Using photon counting experiments, we observe Electromagnetically Induced Transparency based generation and shaping of few-photon sub-Poissonian light pulses.

Journal Article↗

PubMed1994

Managed Care College: a continuing education program for primary care clinicians.

This paper provides an overview of the Metro Medical Group Managed Care College--a new program of continuing medical education in primary care, created by the organization to improve the care it provides and demonstrate a new model that might serve as a prototype for other managed care organizations.

Curriculum↗

PubMed1990

Multi-institutional drug-use evaluation of intraocular irrigating solutions.

A collaborative drug-use evaluation (DUE) of intraocular irrigating solutions (IOISs) at ophthalmic specialty hospitals nationwide is reported. Qualifying criteria for the use of an expensive fortified IOIS product were (1) the duration of surgery is more than 60 minutes, (2) the surgery is performed without a viscoelastic agent, (3) the patient's age is less than 50 years, (4) the patient has diabetes, and (5) the patient has evidence of compromised corneal endothelium. Surgical cases involving the use of IOISs were identified at each institution, and those cases involving fortified IOIS were reviewed for conformance with the criteria established. Of 23 institutions, 10 were able to perform the DUE. The review was concurrent at one institution and retrospective at the other nine. A case had to meet only one criterion to be considered in conformance. The cumulative mean rate of conformance with at least one criterion was 74%; the median conformance rate was 91%. The criteria that most frequently justified the use of fortified IOIS were surgical duration and nonuse of a viscoelastic material. Conformance with the DUE criteria varied with the institution, but valuable knowledge about the use of intraocular irrigating solutions was obtained by all.

Adult↗

PubMed1979

Renal and gastric hamartomas.

This report documents a patient with renal tumor which was originally diagnosed as "Wilms' tumor" and treated by irradiation and chemotherapy. Fifteen years later the patient was found to have gastric hamartomas. Reviews of the kidney tumor revealed it to be composed of morphologic features consistent with renal hamartoma rather than Wilms' tumor. We wish to report this extremely unusual association of renal and gastric hamartomas.

Adolescent↗