Takayoshi Kobayashi

Generation and characterization of a source of wavelength division multiplexing quantum key distribution (2004)

Yabushita, Atsushi, Kobayashi, Takayoshi

Using spontaneous parametric down-conversion, photon pairs entangled in frequency and polarization were generated. After frequency resolving the photon pairs, the polarization correlations were...

Spectroscopy by frequency entangled photon pairs (2003)

Yabushita, Atsushi, Kobayashi, Takayoshi

Quantum spectroscopy was performed using the frequency-entangled broadband photon pairs generated by spontaneous parametric down-conversion. An absorptive sample was placed in front of the idler...

Two-photon interference of multimode two-photon pairs with an unbalanced interferometer (2003)

Goto, Hayato, Wang, Haibo, Horikiri, Tomoyuki, Yanagihara, Yasuo, Kobayashi, Takayoshi

Two-photon interference of multimode two-photon pairs produced by an optical parametric oscillator has been observed for the first time with an unbalanced interferometer. The time correlation between...

Observation of an oscillatory correlation function of multimode two-photon pairs (2003)

Goto, Hayato, Yanagihara, Yasuo, Wang, Haibo, Horikiri, Tomoyuki, Kobayashi, Takayoshi

An oscillatory correlation function has been observed by the coincidence counting of multimode two-photon pairs produced with a degenerate optical parametric oscillator far below threshold. The...

Continuous variable teleportation of single photon states (Proceedings version) (2001)

Ide, Toshiki, Hofmann, Holger F., Kobayashi, Takayoshi, Furusawa, Akira

We investigate the changes to a single photon state caused by the non-maximal entanglement in continuous variable quantum teleportation. It is shown that the teleportation measurement introduces...

Gain tuning and fidelity in continuous variable quantum teleportation (2001)

Ide, Toshiki, Hofmann, Holger F., Furusawa, Akira, Kobayashi, Takayoshi

The fidelity of continuous variable teleportation can be optimized by changing the gain in the modulation of the output field. We discuss the gain dependence of fidelity for coherent, vacuum and one...

Information extraction and quantum state distortions in continuous variable quantum teleportation (2001)

Hofmann, Holger F., Ide, Toshiki, Kobayashi, Takayoshi, Furusawa, Akira

We analyze the loss of fidelity in continuous variable teleportation due to non-maximal entanglement. It is shown that the quantum state distortions correspond to the measurement back-action of a...

Continuous variable teleportation of single photon states (2001)

Ide, Toshiki, Hofmann, Holger F., Kobayashi, Takayoshi, Furusawa, Akira

The properties of continuous variable teleportation of single photon states are investigated. The output state is different from the input state due to the non-maximal entanglement in the EPR beams....

Quantum nondemolition measurement of a light field component by a feedback compensated beam splitter (2001)

Hofmann, Holger F., Kobayashi, Takayoshi, Furusawa, Akira

In conventional quantum nondemolition measurements, the interaction between signal and probe preserves the measured variable. Alternatively, it is possible to restore the original value of the...

Information losses in continuous variable quantum teleportation (2001)

Hofmann, Holger F., Ide, Toshiki, Kobayashi, Takayoshi, Furusawa, Akira

It is shown that the information losses due to the limited fidelity of continuous variable quantum teleportation are equivalent to the losses induced by a beam splitter of appropriate reflectivity.

Photon echo signature of vibrational cat states created by femtosecond excitation of molecules (2000)

Hofmann, Holger F., Fuji, Takao, Kobayashi, Takayoshi

A pair of coherent femtosecond pulse excitations applied to a molecule with strong electron-phonon coupling creates a coherent superposition of a low momentum and a high momentum wavepacket in the...

Molecular photon echoes as a signature of vibrational cat states (2000)

Hofmann, Holger F., Fuji, Takao, Sugita, Atsushi, Kobayashi, Takayoshi

Quantum interference between two distinct vibrational trajectories induced by two pulse femtosecond excitation in molecules is shown to result in a photon echo, providing direct evidence of the cat...

Quantum jumps in backaction evasion measurements of a light field component (2000)

Hofmann, Holger F., Kobayashi, Takayoshi, Furusawa, Akira

Backaction evasion measurements of a quadrature component of the light field vacuum necessarily induce quantum jumps in the photon number. The correlation between measurement results and quantum jump...

Correlations of measurement information and noise in quantum measurements with finite resolution (2000)

Hofmann, Holger F., Kobayashi, Takayoshi, Furusawa, Akira

The original purpose of measurements is to provide us with information about a previously unknown physical property of the system observed. In the Hilbert space formalism of quantum mechanics, this...

Fidelity and information in the quantum teleportation of continuous variables (2000)

Hofmann, Holger F., Ide, Toshiki, Kobayashi, Takayoshi, Furusawa, Akira

Ideally, quantum teleportation should transfer a quantum state without distortion and without providing any information about that state. However, quantum teleportation of continuous electromagnetic...

Nonclassical correlations of photon number and field components in the vacuum state (1999)

Hofmann, Holger F., Kobayashi, Takayoshi, Furusawa, Akira

It is shown that the quantum jumps in the photon number n from zero to one or more photons induced by backaction evasion quantum nondemolition measurements of a quadrature component x of the vacuum...

First International Conference on Organic Nonlinear Optics. Section B: Nonlinear Optics, Principles, Materials, Phenomena, and Devices. (1998)

Kobayashi, Takayoshi, Kajzar, Francois

The Final Proceedings for International Conference on Organic Nonlinear Optics, 9 January 1994 - 13 January 1994. The Final Proceedings for International Conference on Organic Nonlinear Optics, 9...

LO Phonons in CdS(x)Se(1-x) Semiconductor Microcrystallites, (1992)

Kobayashi, Takayoshi, Nomura, Shintaro

It is of interest and importance to study semiconductor microcrystallites as three dimensionally confined system in conjecture with one dimensionally confined quantum well systems. Because the...

HEREDITARY GENERALIZED AMYLOIDOSIS WITH POLYNEUROPATHY: CLINICOPATHOLOGICAL STUDY OF 65 JAPANESE PATIENTS (1987)

IKEDA, SHU-ICHI, HANYU, NORINAO, HONGO, MINORU, YOSHIOKA, JIRO, OGUCHI, HISAO, YANAGISAWA, NOBUO, ...

A clinicopathological study was made on 65 patients from a small area of Nagano Prefecture, Japan, with hereditary generalized amyloidosis with polyneuropathy to clarify the clinical variety of the...

A Short Lived Intermediate in the Photoconversion of Protochlorophyllide to Chlorophyllide a (1981)

Inoue, Yorinao, Kobayashi, Takayoshi, Ogawa, Teruo, Shibata, Kazuo

The transient absorption change for the photoreduction of protochlorophyllide (PChlide) was studied with a solution of extracted PChlide holochrome and with etiolated leaves. The following results...

Kobayashi Laboratory

Kobayashi, Takayoshi

An official site of the Kobayashi Laboratory, Department of Physics,Graduate School of Science, the University of Tokyo. The laboratory conducts research on ultrafast and nonlinear optical processes,...

Primary Processes in Photolysis of Octopus Rhodopsin

Ohtani, Hiroyuki, Kobayashi, Takayoshi, Tsuda, Motoyuki, Ebrey, Thomas G.

The photolysis of octopus rhodopsin was studied by picosecond time-resolved spectroscopy at physiological temperature (8°C) and by steady-state spectroscopy at very low temperature (10 K). Both...

Branching Photocycle of Sensory Rhodopsin in Halobacterium Halobium

Ohtani, Hiroyuki, Kobayashi, Takayoshi, Tsuda, Motoyuki

Temperature effect of the photocyle of sensory rhodopsin (sR) was studied by nanosecond spectroscopy. Though the formation yield of sRM (sR370) was sharply decreased with temperature, those of sRK...

Primary Processes in Photolysis of Octopus Rhodopsin

Ohtani, Hiroyuki, Kobayashi, Takayoshi, Tsuda, Motoyuki, Ebrey, Thomas G.

The photolysis of octopus rhodopsin was studied by picosecond time-resolved spectroscopy at physiological temperature (8°C) and by steady-state spectroscopy at very low temperature (10 K). Both...

Branching Photocycle of Sensory Rhodopsin in Halobacterium Halobium

Ohtani, Hiroyuki, Kobayashi, Takayoshi, Tsuda, Motoyuki

Temperature effect of the photocyle of sensory rhodopsin (sR) was studied by nanosecond spectroscopy. Though the formation yield of sRM (sR370) was sharply decreased with temperature, those of sRK...

Kobayashi Laboratory

Kobayashi, Takayoshi

An official site of the Kobayashi Laboratory, Department of Physics,Graduate School of Science, the University of Tokyo. The laboratory conducts research on ultrafast and nonlinear optical processes,...