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We propose a quantum non-demolition method -giant Faraday rotation -to detect a single electron spin in a quantum dot inside a microcavity where negatively-charged exciton strongly couples to the cavity mode. Left-and right-circularly polarized light reflected from the cavity feels different phase shifts due to cavity quantum electrodynamics and the optical spin selection rule. This yields giant and tunable Faraday rotation which can be easily detected experimentally. Based on this spin-detection technique, a scalable scheme to create an arbitrary amount of entanglement between two or more remote spins via a single photon is proposed.PACS numbers: 78.67. Hc, 03.67.Mn, 42.50.Pq, 78.20.Ek Photons and spins hold great potential in quantum information science, especially for quantum communications, quantum information processing and quantum networks [1]. Photons are ideal candidates to transmit quantum information with little decoherence, whereas spins can be used to store and process quantum information due to their long coherence times. Therefore investigations of spin manipulation, spin detection, remote spin entanglement mediated by photons, and quantum state transfer between photons and spins are of great importance [2,3,4,5,6,7].Spin manipulation is well developed using pulsed magnetic resonance techniques, whereas single spin detection remains a challenging task. Electrical detection of single spin has been reported in a gate-defined quantum box [8,9] and in a silicon field-effect transistor [10]. The optically detected magnetic resonance technique (ODMR) proves to be an effective way to detect a single spin either in a single molecule [11,12] or a single N-V center in diamond [13]. However, the ODMR technique is based on the spin dependent fluorescence such that the spin is destroyed after detection. Recently, a non-demolition method to detect a single electron spin has been experimentally reported by Berezovsky et al [14] and Atatüre et al [15]. Both groups detect the tiny Faraday rotation angle induced by a single electron spin in a quantum dot (QD), so the measured signals (even enhanced by a cavity) are rather weak and noisy.It is widely accepted that entanglement is a useful resource in quantum information science. Recently remote entanglement between photons, trapped ions and atom ensembles have been demonstrated [16,17,18], however, all current experimental proposals for entangling two atoms are restricted to one entanglement bit rather than an arbitrary amount of entanglement [19,20]. To our knowledge, entanglement between remote single spins has not yet been achieved due to the lack of realizable proposals [21,22,23].In this Letter, we propose a quantum non-demolition method -giant Faraday rotation -to detect a single electron spin in a single QD inside a microcavity. The different phase shifts for the left and right circularly polarized light reflected from the QD-cavity system yields giant Faraday rotation which can be easily detected experimentally. This giant Faraday rotation induced by a sin...

We propose an entanglement beam splitter (EBS) using a quantum-dot spin in a double-sided optical microcavity. In contrast to the conventional optical beam splitter, the EBS can directly split a photon-spin product state into two constituent entangled states via transmission and reflection with high fidelity and high efficiency (up to 100 percent). This device is based on giant optical circular birefringence induced by a single spin as a result of cavity quantum electrodynamics and the spin selection rule of trion transition (Pauli blocking). The EBS is robust and it is immune to the fine structure splitting in a realistic quantum dot. This quantum device can be used for deterministically creating photon-spin, photon-photon and spin-spin entanglement as well as a single-shot quantum non-demolition measurement of a single spin. Therefore, the EBS can find wide applications in quantum information science and technology.

We present a deterministic and scalable scheme to generate photon polarization entanglement via a single electron spin confined in a charged quantum dot inside a microcavity. This scheme is based on giant circular birefringence and giant Faraday rotation induced by a single electron spin. Two independent photons are sequentially sent to the cavity and get entangled after measuring the spin state. We show that this scheme can be extended to generate multiphoton polarization entanglement including Greenberger-Horne-Zeilinger states and cluster states in a deterministic way.

We present a scheme for efficient state teleportation and entanglement swapping using a single quantum-dot spin in an optical microcavity based on giant circular birefringence. State teleportation or entanglement swapping is heralded by the sequential detection of two photons, and is finished after the spin measurement. The spin-cavity unit works as a complete Bell-state analyzer with a built-in spin memory allowing loss-resistant repeater operation. This device can work in both the weak coupling and the strong coupling regime, but high efficiencies and high fidelities are only achievable when the side leakage and cavity loss is low. We assess the feasibility of this device, and show it can be implemented with current technology. We also propose a spin manipulation method using single photons, which could be used to preserve the spin coherence via spin echo techniques.

The Raman spectra of a new type of graphite whiskers have been measured in the range of 150-7800 cm Ϫ1. The intensity of the overtone (2D) located at ϳ2700 cm Ϫ1 is found to be about 10 times stronger than that of the CC stretching mode ͑G͒ at 1582 cm Ϫ1. Because of the peculiar enhancement of the 2D mode, high-order Raman bands up to fifth order at ϳ7500 cm Ϫ1 have been observed. Polarized micro-Raman spectroscopy has been performed on an individual graphite whisker, and angular-dependent intensity measurements of all Raman modes in the VV and HV geometries are in agreement with the theoretical calculated results. Laser-energydependent dispersion effects and the frequency discrepancy of Raman modes between their Stokes and anti-Stokes lines in graphite whiskers are also carefully investigated. The energy dispersion of the D mode and G mode is very similar to that of highly oriented pyrolytic graphite ͑HOPG͒. In contrast to the Raman spectra of HOPG and other graphite materials, two laser-energy-dependent Raman lines are revealed in the low-frequency region of the Raman spectra of graphite whiskers, which are believed to be the resonantly enhanced phonons in the transverse-acoustic and longitudinal-acoustic phonon branches. Moreover, the obvious energy dispersion of the DЈ mode at ϳ1620 cm Ϫ1 is observed in graphite whiskers. The results clearly reveal how strongly the peak parameters of Raman modes of graphite materials are dependent on their structural geometry. The Stokes and anti-Stokes scattering experiments show that the frequency discrepancy between the Stokes and anti-Stokes sides of a Raman mode in graphite materials is equal to the frequency value covered by the one-phonon energy of this Raman mode in its frequency versus laser energy curve, which is the product of the one-phonon energy of this mode (E s) and the value of its laser-energy dispersions (‫ץ‬E s ‫ץ/‬ L).

OBJECTIVES: To predict epidermal growth factor receptor (EGFR) mutation status using quantitative radiomic biomarkers and representative clinical variables. METHODS: The study included 180 patients diagnosed as of non-small cell lung cancer (NSCLC) with their pre-therapy computed tomography (CT) scans. Using a radiomic method, 485 features that reflect the heterogeneity and phenotype of tumors were extracted. Afterwards, these radiomic features were used for predicting epidermal growth factor receptor (EGFR) mutation status by a least absolute shrinkage and selection operator (LASSO) based on multivariable logistic regression. As a result, we found that radiomic features have prognostic ability in EGFR mutation status prediction. In addition, we used radiomic nomogram and calibration curve to test the performance of the model. RESULTS: Multivariate analysis revealed that the radiomic features had the potential to build a prediction model for EGFR mutation. The area under the receiver operating characteristic curve (AUC) for the training cohort was 0.8618, and the AUC for the validation cohort was 0.8725, which were superior to prediction model that used clinical variables alone. CONCLUSION: Radiomic features are better predictors of EGFR mutation status than conventional semantic CT image features or clinical variables to help doctors to decide who need EGFR tyrosine kinase inhibitor (TKI) treatment.

We report the efficient coherent photon scattering from a semiconductor quantum dot embedded in a pillar microcavity. We show that a surface acoustic wave can periodically modulate the energy levels of the quantum dot, but has a negligible effect on the cavity mode. The scattered narrow-band laser is converted to a pulsed single-photon stream, displaying an anti-bunching dip characteristic of single-photon emission. Multiple phonon sidebands are resolved in the emission spectrum, due to the absorption and emission of vibrational quanta in each scattering event.