4 results about "Density matrix" patented technology

The application discloses a kind of main distribution network power flow model no solution traceability and correction method, it is related to power system dispatching technical field, including, acquisition real-time measurement data pre-processing, obtain quantum noise intensity coefficient;Quantum state density matrix is generated based on quantum noise intensity coefficient, and quantum fidelity is obtained by characteristic decomposition mapping;Based on quantum fidelity, the minimum eigenvalue is extracted, and the fault node coordinates are located by no solution traceability mapping, and the fault severity index is obtained by negative exponential mapping;Based on fault severity index, no solution traceability grade is divided, and fault scene is output;Based on fault scene, the set of power flow inversion control instructions is obtained, and the power flow no solution risk early warning value is corrected.The quantum fidelity mapping accurately locates the power grid fault source, eradicates the main distribution network model no solution problem, promotes the landing of quantum sensing industry and improves the fault response speed.

The application discloses a two-bit and three-bit unknown state entanglement determination method based on a variational quantum circuit, and comprises the following steps: generating quantum states of a plurality of known state labels based on uniform sampling of a random matrix to obtain a quantum state data set containing a two-bit data set and a three-bit data set; extracting observable operator expectation values from the quantum state data set to generate a classical feature vector; encoding the classical feature vector to an initial quantum state through a parameterized quantum gate; constructing a variational quantum circuit, and making the initial quantum state evolve through the variational quantum circuit to obtain an output state; constructing an objective function based on quantum measurement results of the output state, and outputting an entanglement determination result of the quantum state data according to the objective function value. Compared with a quantum state tomography method which depends on complete density matrix reconstruction, the method only uses observable operator expectation values highly related to entanglement determination as input, and thus significantly reduces measurement resource consumption and classical post-processing burden.

This invention discloses a method and system for hydrological uncertainty analysis based on probability density envelopes, relating to the field of hydrology and water resources technology. The method includes: collecting time series data of hydrological elements and preprocessing them; generating a uniform grid and performing kernel density estimation at the grid points to obtain density estimates; resampling each series to obtain the density matrix of the samples; calculating the standard error of the grid points; constructing candidate subsets, prioritizing the minimization of the probability density envelope area and minimizing the difference between upper and lower overprobabilities as secondary objectives, and optimizing the selection of the optimal multiplier; using the optimal multiplier to calculate the lower and upper probability density envelopes at the grid points and calculating the overprobabilities; extracting feature parameters; and comparing and analyzing the uncertainties of hydrological elements at different stations based on the feature parameters. This invention does not require a pre-defined distribution, can adaptively construct the minimum area simultaneous confidence band, and provides multi-dimensional uncertainty indicators, providing a scientific basis for watershed hydrological analysis and risk management.

This application proposes a quantum state tomography method, apparatus, and storage medium. The quantum state tomography method includes: receiving quantum system specifications and measurement constraints; preparing multiple quantum state replicas based on the quantum system specifications and measurement constraints; analyzing the multiple quantum state replicas based on Hamiltonian evolution to obtain a manifold of a predetermined quantum state; selecting an optimal measurement basis according to the manifold of the predetermined quantum state; acquiring measurement data of the multiple quantum state replicas under the optimal measurement basis to form a compressed measurement set; and generating a compressed measurement protocol based on the compressed measurement set, including: selecting a preset reconstruction algorithm and reconstructing the quantum state density matrix based on the compressed measurement set and the preset reconstruction algorithm. Based on this, this application can exponentially reduce the amount of measurement data, achieve complete state reconstruction of large-scale quantum systems, and ensure reconstruction fidelity.