Search results for "Quantum"
showing 10 items of 9714 documents
Quantum Information by Adiabatic Passage : Quantum Gates and Decoherence
2007
The first part of this thesis is about adiabatic quantum processes designed for the implementation of quantum logic gates, the elementary components of quantumcomputers, by the interaction of pulsed laser fields with atoms. The adiabaticmethods allow robust processes, i.e. which are not sensitive to the fluctuationsof experimental parameters. The processes described in this thesis only requireaccurate control of the polarisations and the relative static phases of thelaser fields. These processes allow the implementation of a universal set ofquantum gates, which make possible the implementation of all the other quantumgates by combinations.The second part of this thesis concerns the effects …
Superradiant Quantum Phase Transition for an Exactly Solvable Two-Qubit Spin-Boson Model
2023
A spin-boson-like model with two interacting qubits is analysed. The model turns out to be exactly solvable since it is characterized by the exchange symmetry between the two spins. The explicit expressions of eigenstates and eigenenergies make it possible to analytically unveil the occurrence of first-order quantum phase transitions. The latter are physically relevant since they are characterized by abrupt changes in the two-spin subsystem concurrence, in the net spin magnetization and in the mean photon number.
Kvanttikoneohjelmointi
2016
Työssä tutkittiin kvanttiohjelmointikielten nykytilaa. Tavoitteena oli pintapuolisesti kartoittaa millaisia kieliä on olemassa, mitä niiden erot ovat ja miksi niitäonkehitetty,vaikkakäytännönkvanttitietokoneitaeivieläolekaan.Tämätutki- mustavoite toteutui hyvin. Johtopäätöksenä voidaan sanoa, että kvanttiohjelmoin- tikieliä on kehitetty suhteellisen paljon kvanttitietokoneiden puuttumiseen nähden, ja ne eroavat monilta osin. Myös niiden kehittämiseen löydettiin paljon hyviä syitä. In this paper the current state of quantum programming languages was studied. The objective was to do a survey of existing languages, their differences, and the reasons for their development, even though practical…
Nanorings driven by a laser field
2013
We present the dynamics of an electron constrained over an 1D ring with radius of 0.142 nm driven by a laser field. The temporal evolution of the system is evaluated by a semi-analytical solution of the full quantum time dependent Schr¨odinger equation. In our calculation the gap energy between the ground and the first excited state of the nanoring is three times the photon energy laser (0.63 eV) and the laser intensity is 4·1014 W/cm2 . Our analysis is performed by considering different polarization states of the incident laser. Our attention is mainly focused on the study of the High Harmonic Generation (HHG), the energy and the angular momentum absorbed by the driven system. We observe 1…
Achievements and Future prospects: Riga, 23–25 April, 2017
2017
Supported by FP7 project "Unlocking and Boosting Research Potential for Photonics in Latvia – Towards Effective Integration in the European Research Area " (FOTONIKA-LV) FP7-REGPOT-CT-2011-285912
Achievements and Future prospects: Book of Abstracts (Riga, 23-24 April, 2015; Latvian Academy of Sciences)
2015
Supported by FP7 project Unlocking and Boosting Research Potential for Photonics in Latvia – Towards Effective Integration in the European Research Area (FOTONIKA-LV) FP7-REGPOT-CT-2011-285912
Achievements and Future prospects: Riga, 24–25 April 2019
2019
Four years after the end of the project:FP7-REGPOT-2011-1, No 285912, FOTONIKA-LV “Unlocking and Boosting Research Potential for Photonics in Latvia – Towards Effective Integration in the European Research Area”
Embracing iterations in Quantum software: a vision
2022
In today’s software engineering, iterations, affordable en masse, form an important part of just about any system. However, not all computing resources are cheap to consume. In High-Performance (HPC) and Quantum Computing (QC), executions can consume considerable amounts of energy and time, which is reserved and used even if the very first steps in the process fail. This means that developers must assume a different attitude towards programming, and aim at error-free software before its execution. This is com monly facilitated using simulators, which are commonplace for both HPC and QC. However the fashion developers advance from one tool to another is ad-hoc, with no established software e…
Correspondence between generalized binomial field states and coherent atomic states
2008
We show that the N-photon generalized binomial states of electromagnetic field may be put in a bijective mapping with the coherent atomic states of N two-level atoms. We exploit this correspondence to simply obtain both known and new properties of the N-photon generalized binomial states. In particular, an over-complete basis of these binomial states and an orthonormal basis are obtained. Finally, the squeezing properties of generalized binomial state are analyzed.
Enhancing Metastability by Dissipation and Driving in an Asymmetric Bistable Quantum System.
2018
The stabilizing effect of quantum fluctuations on the escape process and the relaxation dynamics from a quantum metastable state are investigated. Specifically, the quantum dynamics of a multilevel bistable system coupled to a bosonic Ohmic thermal bath in strong dissipation regime is analyzed. The study is performed by a non-perturbative method based on the real-time path integral approach of the Feynman-Vernon influence functional. We consider a strongly asymmetric double well potential with and without a monochromatic external driving, and with an out-of-equilibrium initial condition. In the absence of driving we observe a nonmonotonic behavior of the escape time from the metastable regi…