The 10−nm-scale structure formed in silicon cleavage is studied by the quantum mechanical calculations of large-scale electronic structure. The cleavage process was simulated and the results show not only the elementa...
The 10−nm-scale structure formed in silicon cleavage is studied by the quantum mechanical calculations of large-scale electronic structure. The cleavage process was simulated and the results show not only the elementary process of the (experimentally observed) (111)-(2×1) surface reconstruction but also several step-formation processes. These processes are studied by analyzing electronic freedom and compared with scanning tunneling microscopy experiments. The stability mechanism of the (111)-(2×1) cleavage mode is presented beyond the traditional approach with surface energy. In other results, the cleavage path was bent into the experimentally observed planes, owing to the relative stability among cleavage modes. Several common aspects between cleavage and other phenomena are discussed from the viewpoints of nonequilibrium process and 10−nm-scale structure.
Cell adhesion surfaces with micro or nano structures were fabricated in microchips. Mouse fibroblasts cultured on the surfaces looked different from those on a tissue culture polystyrene dish. These results indicate t...
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We describe an interferometer which is capable of measuring phase at a Heisenberg limit of 1∕3. The proposed interferometer, which consumes three indistinguishable photons, consists of two beam splitters with two-thi...
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We describe an interferometer which is capable of measuring phase at a Heisenberg limit of 1∕3. The proposed interferometer, which consumes three indistinguishable photons, consists of two beam splitters with two-third reflectivity and two mirrors. It is shown that the oscillation period of the quantum interference is three times shorter than in the classical case and the interference visibility is 100%. A de Broglie wavelength given by λ0∕3 can then be observed in this scheme, where λ0 is the wavelength of a single photon. Compared with similar phase measurements [Mitchell et al., Nature (London) 429, 161 (2004); Walter et al., ibid. 429, 158 (2004)] by multiphoton maximally entangled states (MES), a three-photon MES is not generated in our proposal.
We introduce a quantum component, the quantum high- and low-pass filter, and analyze its output characteristic. It is shown that a quantum bandpass filter can be achieved by using passive linear optics and projection ...
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We introduce a quantum component, the quantum high- and low-pass filter, and analyze its output characteristic. It is shown that a quantum bandpass filter can be achieved by using passive linear optics and projection measurements. Furthermore, we show that the sub-Poissonian state can be generated by using a cascaded quantum low-pass filter and high-pass filter.
We have observed two-photon quantum interference in a Michelson interferometer. For the first time, we experimentally demonstrated two-photon quantum interference patterns, which show the transition from nonsubwavelen...
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We have observed two-photon quantum interference in a Michelson interferometer. For the first time, we experimentally demonstrated two-photon quantum interference patterns, which show the transition from nonsubwavelength interference fringes to the general subwavelength interference. At the same time, a photon bunching effect was also shown by a postselection. The ∣1, 1⟩ state with a single photon in a mode corresponding to each arm of the interferometer was exclusively postselected by using path difference between two arms.
We propose a high security quantum key distribution (QKD) scheme utilizing one mode of spontaneous parametric downconversion gated by a photon number resolving detector. This photon number measurement is possible by u...
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We propose a high security quantum key distribution (QKD) scheme utilizing one mode of spontaneous parametric downconversion gated by a photon number resolving detector. This photon number measurement is possible by using single-photon detectors operating at room temperature and optical fibers. By post selection, the multiphoton probability in this scheme can be reduced to lower than that of a scheme using an attenuated coherent light resulting in improvement of security. Furthermore, if distillation protocol (error correction and privacy amplification) is performed, the gain will be increased. Hence a QKD system with higher security and bit rate than the laser-based QKD system can be attained using present available technologies.
In this paper, we study the theory of spontaneous parametric down-conversion pumped by a short coherent pulse. It is shown that when single spatial mode filters and narrow band optical filters are used to filter the o...
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In this paper, we study the theory of spontaneous parametric down-conversion pumped by a short coherent pulse. It is shown that when single spatial mode filters and narrow band optical filters are used to filter the output state of parametric down-conversion, the postselected state of parametric down-conversion can be approximately described by a simple single-mode theory.
Far-infrared dispersion of the complex dielectric constant in incipient ferroelectric KTaO3 has been revealed by terahertz time-domain spectroscopy (THz-TDS) in the temperature range from 8K to 300K. The real part of ...
Far-infrared dispersion of the complex dielectric constant in incipient ferroelectric KTaO3 has been revealed by terahertz time-domain spectroscopy (THz-TDS) in the temperature range from 8K to 300K. The real part of the complex dielectric constant in the far-infrared region is larger than the static permittivity. Through the analysis using a single Lorentz oscillator model, we conclude that the origin of the extremely large static permittivity in KTaO3 and its anomalous behavior at low temperatures are almost fully attributed to the TO1 mode dispersion and the suppression of the softening.
We propose and demonstrate a new scheme of high-efficiency generation of the three-photon polarization-entangled W state, which is a typical three-qubit entangled state. The high efficiency has enabled the first full ...
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We propose and demonstrate a new scheme of high-efficiency generation of the three-photon polarization-entangled W state, which is a typical three-qubit entangled state. The high efficiency has enabled the first full characterization of the state by quantum state tomography. We have analyzed the obtained state and observed its nature of tripartite entanglement and robustness of entanglement.
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