Abstract: According to an aspect of the present invention, there is provided a resonator including: a transmission line including a conductor line with a bent portion, wherein the conductor line has a plurality of slits formed therein, the slits being formed in an extending direction of the conductor line to pass through the bent portion, and wherein the slits are formed to have intervals that become narrower from an outer-side toward an inner-side of the bent portion.

Abstract: In the method of the present invention, one of each pair of photons connected through entanglement is distributed to a transmitting station, relay stations and a receiving station. After the photons reach secure sites, such as the relay stations, a base for detecting photons is determined between adjacent sites, and then photons are detected in each site, which makes it possible to obtain a secret key used for secure information transmission between relay stations using bases coincide with each other every time. Also, in the present invention, a high-quality random number sequence serving as a secret key is automatically generated in a physical manner every time by detecting a superposition state of an entanglement and procedures corresponding to those in which a secret key itself is transmitted in a form of a quantum cryptogram are performed.

Abstract: Quantum computer includes optical resonator including system group containing systems each having energy states highest-energy state |3>, and other two energy states |1> and |2>, fourth or more states |p>, transition angular frequency (?ij) between |i> and |j>, homogeneous broadening (??homo,ij) in transition angular frequency between |i> and |j>, optical resonator having resonator modes, ?ck of kth resonator mode, and emitting unit configured to emit light beam to system group, and wherein |?cl??cm|>??homo,23, system group includes system subgroups Aq having respective ?23 which resonate with respective ?cq of resonator modes, and emitting unit is arranged to apply light beam of two wavelengths and other light beam to s(1)th quantum bit Aqs(1) (s(1)1˜r) formed of r systems selected from each Aq, light beam of two wavelengths simultaneously causing two-photon resonance on Aq at ?12 or ?1p, other light beam simultaneously causing one-photon resonance on Aq at ?13 or ?p3.

Abstract: A filter includes a resonant unit which has a plurality of resonators respectively formed of each microstrip line and connected in cascade with one another, and a coupling unit which has at least one inter-resonator coupling of the resonant unit in an area within a range of ±45° (?-wavelength) in an electrical length from a voltage maximum point at a intermediate of the microstrip line.

Abstract: A quantum communication apparatus is used in operations to generate entanglement between the two physical system ensembles and operations to extend the distance between entangled ensembles by connecting pairs of entangled ensembles. The apparatus uses only passive elements without any actuating parts, active devices having no mechanically actuating parts, such as an electro-optical device capable of ultrahigh-speed operation, and a laser source capable of generating high-speed pulse trains or a continuous wave laser source. The apparatus can rapidly execute light irradiation necessary for entanglement generation and connection, and detection of a generated photon at the needed sites within a decoherence time of the physical system.

Abstract: A quantum communication apparatus is used in operations to generate entanglement between the two physical system ensembles and operations to extend the distance between entangled ensembles by connecting pairs of entangled ensembles. The apparatus uses only passive elements without any actuating parts, active devices having no mechanically actuating parts, such as an electro-optical device capable of ultrahigh-speed operation, and a laser source capable of generating high-speed pulse trains or a continuous wave laser source. The apparatus can rapidly execute light irradiation necessary for entanglement generation and connection, and detection of a generated photon at the needed sites within a decoherence time of the physical system.

Abstract: A filter includes a resonant unit which has a plurality of resonators respectively formed of each microstrip line and connected in cascade with one another, and a coupling unit which has at least one inter-resonator coupling of the resonant unit in an area within a range of ±45° (?-wavelength) in an electrical length from a voltage maximum point at a intermediate of the microstrip line.

Abstract: There is provided with a filter circuit, including: an input terminal configured to input signals; a band stop filter configured to have a center frequency of input signals from the input terminal in a stop band and configured to reflect signals in the stop band that is included in the input signals and pass signals outside the stop band; a band pass filter configured to have a pass band including the stop band, and configured to pass signals in the pass band out of the signals having passed through the band stop filter; a synthesis circuit configured to synthesize the signals reflected on the band stop filter and the signals having passed through the band pass filter to obtain synthesis signals; and an output terminal configured to output the synthesis signals.

Abstract: In resonant elements 102 to 105 constituting a resonant circuit, an uncontrolled cross coupling which exists between two resonant elements is controlled by using a coupling element 106 which is newly arranged between the resonant elements, whereby it is possible to create a state where two resonant elements are not coupled with each other or a state where the amount of the coupling is reduced, which states are difficult to be realized on a plane. As a result, it is possible to improve characteristics of a planar filter.

Abstract: A multiplexer includes: a first band-pass filter for a first channel, which is formed in a microstrip line on a dielectric substrate and has a first branching characteristic having a center frequency of f1 and an attenuation pole at a frequency of fa1; and a second band-pass filter for a second channel, which is formed in a microstrip line on a dielectric substrate and has a second branching characteristic having a center frequency of f2 and an attenuation pole at a frequency of fa2. The following relationships (1) to (5) are satisfied: (1) f1<f2; (2) f1<fa1; (3) fa2<f2; (4) f2?fa1<(f2?f1)/2; and (5) fa2?f1<(f2?f1)/2. The second branching characteristic exhibits ?20 dB or less at the frequency of fa1 and the first branching characteristic exhibits ?20 dB or less at the frequency of fa2.

Abstract: In a filter circuit, a conductor layer is formed on one side of a dielectric substrate, and a resonator pattern of resonators, input and sections are formed of micro strip lines on the other side of the dielectric substrate. A transmission line coupling the resonators and is also formed of a micro strip line on the other side. An open stub branches off from the transmission line, and the electric length of this open stub is set to an integral multiple of a half-wave length of a resonance wave length corresponding to a resonance frequency of the filter.

Abstract: A filter includes a resonant unit which has a plurality of resonators respectively formed of each microstrip line and connected in cascade with one another, and a coupling unit which has at least one inter-resonator coupling of the resonant unit in an area within a range of ±45° (?-wavelength) in an electrical length from a voltage maximum point at a intermediate of the microstrip line.

Abstract: A quantum memory includes memory cells each comprising a physical system ensemble, quantum information of the physical system ensemble being expressed by a quantum state of whole amount of the total angular momentum of the physical systems, and the memory cells including two storage memory cells storing the quantum state and a transfer memory cell transferring the quantum state, only two of the memory cells being present on a straight line. The quantum memory also includes a magnet applying a magnetic field to the two storage memory cells and the transfer memory cell, a first light source irradiating the two storage memory cells and the transfer memory cell with right-handed or left-handed polarized light, a second light source simultaneously irradiating one of the two storage memory cells and the transfer memory cell with a laser beam, and a detector detecting a polarization state of the laser beam.

Abstract: Quantum computer includes optical resonator including system group containing systems each having energy states highest-energy state |3>, and other two energy states |1> and |2>, fourth or more states |p>, transition angular frequency (?ij) between |i> and |j>, homogeneous broadening (??homo,ij) in transition angular frequency between |i> and |j>, optical resonator having resonator modes, ?ck of kth resonator mode, and emitting unit configured to emit light beam to system group, and wherein |?cl??cm|>??homo,23, system group includes system subgroups Aq having respective ?23 which resonate with respective ?cq of resonator modes, and emitting unit is arranged to apply light beam of two wavelengths and other light beam to s(1)th quantum bit Aqs(1) (s(1)1˜r) formed of r systems selected from each Aq, light beam of two wavelengths simultaneously causing two-photon resonance on Aq at ?12 or ?1p, other light beam simultaneously causing one-photon resonance on Aq at ?13 or ?p3.

Abstract: A quantum memory includes memory cells each comprising a physical system ensemble, quantum information of the physical system ensemble being expressed by a quantum state of whole amount of the total angular momentum of the physical systems, and the memory cells including two storage memory cells storing the quantum state and a transfer memory cell transferring the quantum state, only two of the memory cells being present on a straight line. The quantum memory also includes a magnet applying a magnetic field to the two storage memory cells and the transfer memory cell, a first light source irradiating the two storage memory cells and the transfer memory cell with right-handed or left-handed polarized light, a second light source simultaneously irradiating one of the two storage memory cells and the transfer memory cell with a laser beam, and a detector detecting a polarization state of the laser beam.

Abstract: In the method of the present invention, one of each pair of photons connected through entanglement is distributed to a transmitting station, relay stations and a receiving station. After the photons reach secure sites, such as the relay stations, a base for detecting photons is determined between adjacent sites, and then photons are detected in each site, which makes it possible to obtain a secret key used for secure information transmission between relay stations using bases coincide with each other every time. Also, in the present invention, a high-quality random number sequence serving as a secret key is automatically generated in a physical manner every time by detecting a superposition state of an entanglement and procedures corresponding to those in which a secret key itself is transmitted in a form of a quantum cryptogram are performed.

Abstract: A quantum memory includes memory cells each comprising a physical system ensemble, quantum information of the physical system ensemble being expressed by a quantum state of whole amount of the total angular momentum of the physical systems, and the memory cells including two storage memory cells storing the quantum state and a transfer memory cell transferring the quantum state, only two of the memory cells being present on a straight line. The quantum memory also includes a magnet applying a magnetic field to the two storage memory cells and the transfer memory cell, a first light source irradiating the two storage memory cells and the transfer memory cell with right-handed or left-handed polarized light, a second light source simultaneously irradiating one of the two storage memory cells and the transfer memory cell with a laser beam, and a detector detecting a polarization state of the laser beam.

Abstract: A quantum memory includes memory cells each comprising a physical system ensemble, quantum information of the physical system ensemble being expressed by a quantum state of whole amount of the total angular momentum of the physical systems, and the memory cells including two storage memory cells storing the quantum state and a transfer memory cell transferring the quantum state, only two of the memory cells being present on a straight line. The quantum memory also includes a magnet applying a magnetic field to the two storage memory cells and the transfer memory cell, a first light source irradiating the two storage memory cells and the transfer memory cell with right-handed or left-handed polarized light, a second light source simultaneously irradiating one of the two storage memory cells and the transfer memory cell with a laser beam, and a detector detecting a polarization state of the laser beam.

Abstract: A quantum communication apparatus is used in operations to generate entanglement between the two physical system ensembles and operations to extend the distance between entangled ensembles by connecting pairs of entangled ensembles. The apparatus uses only passive elements without any actuating parts, active devices having no mechanically actuating parts, such as an electro-optical device capable of ultrahigh-speed operation, and a laser source capable of generating high-speed pulse trains or a continuous wave laser source. The apparatus can rapidly execute light irradiation necessary for entanglement generation and connection, and detection of a generated photon at the needed sites within a decoherence time of the physical system.