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bathaee--marziehsadat
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Turn of Geometric Phase to Topological Phase in Gaussian Structured Light
, M.Sc. Thesis Sharif University of Technology ; Bahrampour, Alireza (Supervisor) ; Bathaee, Marziehsadat (Supervisor)
Abstract
One of the challenging issues in quantum technologies is to be proper control of quantum systems. This plays an important role in a variety of physics fields such as quantum computation, simulation, information etc. Undesirable effects as well as presence of noises in real systems disturb the preferable quantum system evolution. Since a geometric phase (GP) caused from the Holonomy corresponding to a Hilbert space does not depend on the path parameter, it is independent of dynamical evolutions which can introduce control noises. Therefore, the GPs can be adequate candidates for implementing noise resistance quantum gates. Recently, [1] investigated a formalism in which the GP accumulated in...
Optimal control of the power adiabatic stroke of an optomechanical heat engine
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 94, Issue 2 , 2016 ; 15393755 (ISSN) ; Bahrampour, A. R ; Sharif University of Technology
American Physical Society
2016
Abstract
We consider the power adiabatic stroke of the Otto optomechanical heat engine introduced in Phys. Rev. Lett. 112, 150602 (2014)PRLTAO0031-900710.1103/PhysRevLett.112.150602. We derive the maximum extractable work of both optomechanical normal modes in the minimum time while the system experiences quantum friction effects. We show that the total work done by the system in the power adiabatic stroke is optimized by a bang-bang control. The time duration of the power adiabatic stroke is of the order of the inverse of the effective optomechanical-coupling coefficient. The optimal phase-space trajectory of the Otto cycle for both optomechanical normal modes is also obtained
Entangled-based quantum wavelength-division-multiplexing and multiple-access networks
, Article Entropy ; Volume 25, Issue 12 , 2023 ; 10994300 (ISSN) ; Salehi, J. A ; Sharif University of Technology
Multidisciplinary Digital Publishing Institute (MDPI)
2023
Abstract
This paper investigates the mathematical model of the quantum wavelength-division-multiplexing (WDM) network based on the entanglement distribution with the least required wavelengths and passive devices. By adequately utilizing wavelength multiplexers, demultiplexers, and star couplers, N wavelengths are enough to distribute the entanglement among each pair of N users. Moreover, the number of devices employed is reduced by substituting a waveguide grating router for multiplexers and demultiplexers. Furthermore, this study examines implementing the BBM92 quantum key distribution in an entangled-based quantum WDM network. The proposed scheme in this paper may be applied to potential...
3D Trapping, Cooling of a Nanoparticle and Optimal Control of a Heat Engine in a Quantum Optomechanical System
, Ph.D. Dissertation Sharif University of Technology ; Bahrampour, Alireza (Supervisor)
Abstract
In this dissertation, we propose and analytically investigate a scheme for effective three-dimensional cooling of a nanoparticle optically trapped in a Fabry-Perot cavity using multiple cavity modes. By employing active feedback cooling using amplitude modulation of cavity modes, our approach allows to access the UHV regime without the need for any additional means like an external tweezer or a radio-frequency trapping approach. For a set of feasible experimental parameters, we demonstrate that the cooling rates achievable are sufficient to overcompensate recoil heating. Therefore the approach is suited to trap a particle for indefinite times at UHV pressures, where air damping cannot...
A bandwidth-efficient scheme for distributed storage systems
, Article 2008 2nd International Symposium on Advanced Networks and Telecommunication Systems, ANTS 2008, Mumbai, 15 December 2008 through 17 December 2008 ; May , 2008 ; 1424436001 (ISBN); 9781424436002 (ISBN) ; Pakravan, M. R ; Sharif University of Technology
2008
Abstract
In this paper, utilizing the benefits of network coding, we introduce a scheme for uncoordinated dynamic distributed storage systems in which nodes can randomly join and leave the storage network. The proposed scheme can reduce the bandwidth requirement of the storage network
Feedforward-assisted coherent-state comparison amplifier
, Article Physical Review A ; Volume 100, Issue 4 , 2019 ; 24699926 (ISSN) ; Marjan, N ; Bahrampour, A. R ; Sharif University of Technology
American Physical Society
2019
Abstract
Quantum optical coherent-state comparison amplifiers are nondeterministic devices which can amplify rather noiselessly a weak coherent state with an unknown phase from a finite discrete set. The high fidelity and high success probability of this amplifier are accomplished by a comparison stage and some photon subtraction stages. Due to the heralding nature of these amplifiers, they work part of the time. Here, we propose a feedforward protocol to increase the heralded times by correcting the incorrect guess. Hence, we enhance the fidelity and success probability more. Finally, the schematic experimental configuration of the feedforward-assisted coherent-state comparison amplifier is...
Quantum wavelength-division-multiplexing and multiple-access communication systems and networks: Global and unified approach
, Article Physical Review A ; Volume 107, Issue 1 , 2023 ; 24699926 (ISSN) ; Rezai, M ; Salehi, J. A ; Sharif University of Technology
American Physical Society
2023
Abstract
The march towards successful global quantum internet requires introducing all-quantum networks and signal processing techniques. In this paper, we develop and discuss methods for various wavelength-division-multiplexing and multiple-access (WDM) communication systems and networks in fully quantum mechanical terms to obtain all-quantum WDM (QWDM) systems and networks. We begin the paper with a detailed discussion on various possible narrow-band and wideband sources of light signals used in typical WDM systems, such as coherent, number, and Poissonian mixed states. After introducing a generic and fully quantum mechanical WDM network, we develop methodologies for obtaining the necessary...
Driving of Quantum Hamiltonian Relative to The One Dimentional Cavity With Oscilating Mirror and Semi-Transparent Mirror
, M.Sc. Thesis Sharif University of Technology ; Bahrampour, Alireza (Supervisor)
Abstract
The concept of entanglement exists in the common area of the quantum optics and quantum information. Quantum optics is the best tools for investigating of this quantum informational phenomenon experimentally. One of the instruments that let us observes experimentally macroscopy entangeled state is Fabry-Perot Cavity. Striking of photons with the mirror of cavity transfer effective mommentom to it, and oscilating of mirror creates new modes: stocks and anti-stocks modes. Studing quantum state of these modes shows the entangling between photon and phonon (oscilating of mirror) modes. We assume that light beam enters the cavity from a semi-transparent mirror. So cavity is the system with...
Utilizing network coding for file dessimination in peer-to-peer systems
, Article 3rd International Conference on New Technologies, Mobility and Security, NTMS 2009, 20 December 2009 through 23 December 2009, Cairo ; 2009 ; 9781424462735 (ISBN) ; Movaghar, A ; Sadat Bathaee, N ; Sharif University of Technology
2009
Abstract
Network coding was first introduced in information theory for increasing the multicast rate in the networks with directed links. We can model many of the content distribution networks and overlay networks with such a network. Therefore, the solutions introduced in information theory can be used in these networks. In this paper, we analyze using of network coding in uncoordinated cooperative content distribution systems. Reaching the optimum performance in an uncoordinated system needs blocks of the system to be "equally important". In that case, we can retrieve the whole data without need of central controller or complex algorithms. In part of this paper, we exactly define the concept of...
Theoretical Investigation of Quantum Optical Amplifiers in Quantum Communications
, M.Sc. Thesis Sharif University of Technology ; Bahrampour, Alireza (Supervisor) ; Bathaee, Marzieh Sadat (Co-Supervisor)
Abstract
Signal transmission of information on noiseless and lossy channels is an important issue in data transmission. Using the amplifier in the transmission channels is a good solution to help send information on longer channels. In classical communication, information can be coded in the amplitude or phase of the field and an amplifier is responsible for amplifying these parameters. If we consider the conditions ideal and ignore electrical noises, Classical mechanics does not impose any restrictions on the amplification of arbitrary classical signals. Instead, in quantum telecommunications the information encoded on the quadrature of the electromagnetic field are mounted on quantum states, such...
Application of static synchronous series compensator to damp sub-synchronous resonance
, Article 2006 International Conference on Power Electronics, Drives and Energy Systems, PEDES '06, New Delhi, 12 December 2006 through 15 December 2006 ; 2006 ; 078039772X (ISBN); 9780780397729 (ISBN) ; Lashkar Ara, A ; Ehsan, M ; Fotuhi Firuzabad, M ; Bathaee, M. T ; Sharif University of Technology
2006
Abstract
In this paper, a Static Synchronous Series Compensator (SSSC) is used to avoid torsional mode instability in a series compensated transmission system. The power system used in this study is the IEEE first benchmark model for Sub-Synchronous Resonance (SSR) analysis. Simulation results in time domain using PSCAD/EMTDC presented and discussed. ©2006 IEEE