10 results about "Vacuum state" patented technology

The present disclosure relates to a system and a method of performing Gaussian boson sampling via time multiplexing correlation of squeezed vacuum states for quantum information experiments. One embodiment relates to a method for performing Gaussian boson sampling comprising the steps of—generating a set of pulsed pairs of squeezed vacuum states,—performing time 2024 / 038212 multiplexed correlation of multiple of such pairs of squeezed vacuum states,—measuring, via a homodyne detection, a state from the pairs of generated squeezed vacuum states,—feed-forwarding the homodyne result of the measured states to a displacement unit,—performing displacement operations on the remaining state from the pairs of generated squeezed vacuum states, and—counting the states output from the displacement unit.

A high-speed quantum random number generator based on a vacuum state fluctuation technology includes a laser light source (1), an unequal proportion optical splitter (2), a programmable logic device (3), n differential detectors (4), and n groups of amplifiers (5) and analog-to-digital converters (6) connected sequentially. A laser signal emitted by the laser light source (1) is divided into n first light beams and n second light beams by the unequal proportion optical splitter (2). Each of the first light beams and one corresponding second light beam are input to input ends of one of the differential detectors (4). An output end of each of the differential detectors (4) is correspondingly connected to an input end of one of the amplifiers (5). An output end of the analog-to-digital converter (6) is connected to an input end of the programmable logic device (3).

A high-speed quantum random number generator includes a laser light source, an unequal proportion optical splitter configured split a laser signal emitted by the laser light source into n first light beams and n second light beams, n differential detectors, n amplifiers, n analog-to-digital converters, and a programmable logic device. Input ends of each of the differential detectors is coupled to the unequal proportion optical splitter and configured to receive one of the first light beams and one of the second light beams. An input end of each of the amplifiers is coupled to an output end of a corresponding one of the differential detectors. An input end of each of the analog-to-digital converters is coupled to an output end of a corresponding one of the amplifiers. An output end of each of the analog-to-digital converters is connected to an input end of the programmable logic device.

The present disclosure relates to a system for forming continuous variable cluster states and quantum correlations with microwaves comprising a cryogenic chamber (161) with a cryocooler, a superconducting parametric circuit (110), SPC, comprising a resonator (111), a pumping circuitry (140) arrange to pump said SPC (110) with three or more microwave signals (260) to form a pump field (280) in the resonator (111), control circuitry (180) arranged to control the pumping circuitry (140). The cryocooler is arranged to prepare a vacuum state inside the cryogenic chamber (161), and the control circuitry (180) is arranged to control the pumping circuitry (140) to pump the SPC (110) with microwave signals (260). The pump field in the resonator (111) mixes with frequency components of the quantum fluctuations (240) at the vacuum level to generate quadrature-squeezed states of microwave electromagnetic waves (290) which form a continuous variable cluster state.

The application provides a kind of quantum bit fast reading method based on resonant cavity field strength strict control, belong to quantum computing and quantum information processing technical field, this method includes: extracting the readout resonant cavity coupled with quantum bit, obtains the key parameter of readout resonant cavity;Set driving signal frequency and calculate the detuning of ground state and excited state;Design pulse-maintain two-section type driving signal, determine the matching relationship of two pulse amplitudes, generate two-section type microwave driving signal;Two-section type microwave driving signal is applied to readout resonant cavity, carry out the fast response of resonant cavity field strength;Establish strict stable condition, so that cavity field reaches stable value strictly;Based on the coupling effect of superconducting quantum bit and readout resonant cavity, determine quantum bit state through dispersion model;After reading, quickly empty the photon in cavity to vacuum state, realize fast reset.The application realizes resonant cavity field strength fast response and reset through field strength strict control, realizes the fast, accurate reading of quantum bit.

This invention relates to the field of quantum communication technology and discloses an anti-interference quantum key distribution protocol optimization method, comprising: acquiring the single-photon counter count statistics output by the measurement end during the key screening stage, including signal state, decoy state, and vacuum state count values; calculating the instantaneous variance of the vacuum state count value and determining a counting correction parameter based on the ratio of the variance to the signal state count value; using the parameter to correct the gain deviation of the single-photon counter count statistics; extracting the polarization deviation feature vector from the corrected statistics and determining the bit offset parameter; and performing bit-level logic remapping on the key screening sequence based on the bit offset parameter to compensate for channel disturbances when the polarization control voltage at the measurement end is constant. This invention converts the basis vector deflection into an address offset through protocol layer logic mapping, eliminates the occupation of the link by hardware calibration, ensures the continuity of key generation under environmental disturbances, avoids background noise introduced by strong light pilots, and improves quantum key distribution efficiency.

The invention provides a quick quantum bit reading method based on strict control of resonant cavity field intensity, and belongs to the technical field of quantum calculation and quantum information processing.The method comprises the steps that a reading resonant cavity coupled with quantum bits is extracted, and key parameters of the reading resonant cavity are obtained; setting a driving signal frequency and calculating detuning amounts of a ground state and an excitation state; designing a pulse-maintaining two-section type driving signal, determining a matching relation of two sections of pulse amplitudes, and generating a two-section type microwave driving signal; the two-section type microwave driving signal is applied to the read-out resonant cavity, and quick response of the field intensity of the resonant cavity is carried out; a strict stable condition is established, so that the cavity field strictly reaches a stable value; based on the coupling effect of the superconducting quantum bit and the read-out resonant cavity, the quantum bit state is judged through a dispersion model; after reading is completed, photons in the cavity are rapidly emptied to a vacuum state, and rapid reset is achieved. Rapid response and reset of the field intensity of the resonant cavity are realized through strict control of the field intensity, and rapid and accurate reading of quantum bits is realized.

The application discloses a kind of based on the method and system of quantum random number generation of decoy state of ubiquitous light source, the method can be applied in quantum random number generator system not depending on specific light source distribution.This method is prepared by party Alice, and the received optical pulse is randomly modulated into signal state, decoy state and vacuum state, then the modulated optical pulse is randomly prepared into one of four different encoding states, and is sent to measuring party Bob;Measuring party Bob randomly selects base vector to project the encoding state sent to carry out measurement, and obtains output result;Gain under corresponding optical pulse intensity is calculated, and channel parameters and randomness size are estimated based on the calculated gain using decoy state method;According to the randomness size, random number is extracted in measurement result.The application does not depend on specific light source distribution, and has universality.

There is provided a method for resetting an arbitrary state, hosted in a quantum system, to the vacuum Fock state or a coherent state, wherein the quantum system comprises: (I) at least one resonant portion configured to have a first mode having a first resonant frequency and wherein the arbitrary state is hosted in the first mode, (II) a non-linear element coupled to the at least one resonant portion so as to non-linearly couple to the first mode, and (III) one or more signal generator(s) coupled to the at least one resonant portion and / or to the non-linear element and configured to input control signals to physically stabilize a cat qubit subspace in the first mode having a cat phase angle. The method comprises: (i) physically stabilizing for a first period of time, with the one or more signal generator(s), a first cat qubit subspace having a first cat phase angle and first cat size ΙαΙ2, wherein α is a first amplitude which is the amplitude of the superposed coherent states Ι ± α > defining the first cat qubit subspace (702); (ii) after the first period of time, physically performing for a second period of time, with the one or more signal generator(s), a first parallel displacement drive by inputting electromagnetic radiation having a first phase substantially equal with the first cat phase angle, a frequency substantially equal to the first resonant frequency, and a first displacement amplitude greater than or equal to the first amplitude (704); (iii) after the second period of time, physically stabilizing for a third period of time, with the one or more signal generator(s), a second cat qubit subspace having a second cat phase angle which is substantially equal to the first cat phase angle and second cat size ΙβΙ2, wherein β is a second amplitude which is the amplitude of the superposed coherent states Ι ± β > defining the first cat qubit subspace, such that a coherent state Ιβ> with the second amplitude β is stabilized in the first mode (706). There is also provided a corresponding quantum processor, a computer program product, and a computer-readable medium.