Simple scheme for two-qubit Grover search in cavity QED

Following the proposal by F. Yamaguchi et al.[Phys. Rev. A 66, 010302 (R) (2002)], we present an alternative way to implement the two-qubit Grover search algorithm in cavity QED. Compared with F. Yamaguchi et al.'s proposal, with a strong resonant classical field added, our method is insensitive to both the cavity decay and thermal field, and doesn't require that the cavity remain in the vacuum state throughout the procedure. Moreover, the qubit definitions are the same for both atoms, which makes the experiment easier. The strictly numerical simulation shows that our proposal is good enough to demonstrate a two-qubit Grover's search with high fidelity.Comment: manuscript 10 pages, 2 figures, to appear in Phys. Rev.

Corrections to the thermodynamics of Schwarzschild-Tangherlini black hole and the generalized uncertainty principle

We investigate the thermodynamics of Schwarzschild-Tangherlini black hole in the context of the generalized uncertainty principle. The corrections to the Hawking temperature, entropy and the heat capacity are obtained via the modified Hamilton-Jacobi equation. These modifications show that the GUP changes the evolution of Schwarzschild-Tangherlini black hole. Specially, the GUP effect becomes susceptible when the radius or mass of black hole approach to the order of Planck scale, it stops radiating and leads to black hole remnant. Meanwhile, the Planck scale remnant can be confirmed through the analysis of the heat capacity. Those phenomenons imply that the GUP may give a way to solve the information paradox. Besides, we also investigate the possibilities to observe the black hole at LHC, the results demonstrate that the black hole can not be produced in the recent LHC.Comment: 12 pages, 6 figure

Thermal conductivity and rheology behavior of aqueous nanofluids containing alumina and carbon nanotubes

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.In this study, thermal conductivity and rheology behavior of aqueous alumina and multi-walled carbon nanotube (MWCNT) nanofluids were measured and compared with several analytical models. Both thermal conductivity and viscosity of the two nanofluids increase with increasing volume fraction. The experimental thermal conductivity data for the two nanofluids are located near the lower Hashin-Shtrikman bound and far away from the upper Hashin-Shtrikman bound. Therefore there is still enough room for thermal conductivity enhancement. Further conductivity enhancement of the nanofluids can be achieved by manipulating particle or agglomeration distribution and morphology. The structure-property relationship was checked for the nanofluids. Possible agglomeration size and interfacial thermal resistance were obtained and partially validated. Based on the Chen et al. model, a revised model was developed by incorporating the effects of interfacial thermal resistance into the Hamilton-Crosser model. The revised model can accurately reproduce the experimental data based on the agglomeration size extracted from the rheology analysis. In addition, thermal conductivity change of the alumina/water nanofluid with elapsed time was also investigated. The average thermal conductivity decreases with elapsed time. Besides, thermal conductivity measurements were conducted for nanofluid mixtures of alumina/water and MWCNT/water nanofluids

Entanglement of separate nitrogen-vacancy centers coupled to a whispering-gallery mode cavity

We present a quantum electrodynamical model involving nitrogen-vacancy centers coupled to a whispering-gallery mode cavity. Two schemes are considered to create W state and Bell state, respectively. One of the schemes makes use of the Raman transition with the cavity field virtually excited; The other enables the Bell state preparation and quantum information transfer by virtue of dark state evolution and adiabatic passage, which is tolerant to ambient noise and experimental parameter fluctuations. We justify our schemes by considering the experimental feasibility and challenge using currently available technology.Comment: 8 pages and 5 figure