34 research outputs found
Biotope Protection Problems in Tervete Nature Park
Tervete Nature Park is a particular cultural, historical and geographical object. To overcome problems with regard to the existing biotope protection, the inventory of woodland key habitats and natural meadows has been carried out using aprrobated research methods. Great biological diversity including great amount of medical and rare plants found in the Park has been described. Spridisu and Auziņu meadows are typical dry meadows. Silalibiesu, Illenu and Plavnieku meadows are moderately moistured meadows. Meadows' flora of Tervete Nature Park is formed by two vegetation classes: Molinio-Arrhenatheretea and Festuco-Brometea. A complex of measures has been offered to maintain biological diversity as will as for woodland biotopes and utilization of natural meadows
Angular Schmidt Modes in Spontaneous Parametric Down-Conversion
We report a proof-of-principle experiment demonstrating that appropriately
chosen set of Hermite-Gaussian modes constitutes a Schmidt decomposition for
transverse momentum states of biphotons generated in the process of spontaneous
parametric down conversion. We experimentally realize projective measurements
in Schmidt basis and observe correlations between appropriate pairs of modes.
We perform tomographical state reconstruction in the Schmidt basis, by direct
measurement of single-photon density matrix eigenvalues.Comment: 5 pages, 4 figure
Learning the tensor network model of a quantum state using a few single-qubit measurements
The constantly increasing dimensionality of artificial quantum systems
demands for highly efficient methods for their characterization and
benchmarking. Conventional quantum tomography fails for larger systems due to
the exponential growth of the required number of measurements. The conceptual
solution for this dimensionality curse relies on a simple idea - a complete
description of a quantum state is excessive and can be discarded in favor of
experimentally accessible information about the system. The probably
approximately correct (PAC) learning theory has been recently successfully
applied to a problem of building accurate predictors for the measurement
outcomes using a dataset which scales only linearly with the number of qubits.
Here we present a constructive and numerically efficient protocol which learns
a tensor network model of an unknown quantum system. We discuss the limitations
and the scalability of the proposed method.Comment: 10 pages, 11 figure
Two-qubit quantum photonic processor manufactured by femtosecond laser writing
We present an experimental implementation of a two-qubit photonic quantum
processor fabricated using femtosecond laser writing technology. We employ
femtosecond laser writing to create a low-loss reconfigurable photonic chip
implementing precise single-qubit and two-qubit operations. The performance of
single-qubit and two-qubit gates is characterized by full process tomography.
An exemplary application of the processor to determining the ground state
energy of an H2 molecule using the variational quantum eigensolver algorithm is
demonstrated. Our results highlight the potential of femtosecond laser writing
technology to deliver high quality small-scale quantum photonic processors.Comment: 20 pages, 15 figure