Search results for "FREQUENCY"
showing 10 items of 2158 documents
Quantum Nondemolition Measurement and Quantum State Manipulation in Two Dimensional Trapped Ion
2001
An extension of QNDmeasuremen t of the vibrational energy of the trapped ion from one dimensional case to the bidimensional one is presented. Our approach exploits the fixed phase difference existing between the two orthogonal and appropriately configured classical laser beams determining the vibronic coupling. We in fact show that this phase difference may play the role of an adjustable external parameter which allows to optimize the measurement scheme itself in terms of both precision and sensitivity. Our proposal provides a cooling method for the trapped ion from the vibrational thermal state. Due to the coherent superposition of two sub Rabi oscillations, the Rabi frequency degeneration…
Complex quantum state generation and coherent control based on integrated frequency combs
2019
The investigation of integrated frequency comb sources characterized by equidistant spectral modes was initially driven by considerations towards classical applications, seeking a more practical and miniaturized way to generate stable broadband sources of light. Recently, in the context of scaling the complexity of optical quantum circuits, these on-chip approaches have provided a new framework to address the challenges associated with non-classical state generation and manipulation. For example, multi-photon and high-dimensional states were to date either inaccessible, lacked scalability, or were difficult to manipulate, requiring elaborate approaches. The emerging field of quantum frequen…
Generation and coherent manipulation of complex quantum states based on integrated frequency combs
2018
The investigation and use of integrated frequency comb sources (i.e. featured by equally-spaced discrete spectral modes) have recently provided a unique framework to address the challenges of generation and coherent manipulation of complex quantum states in on-chip devices. We exploit integrated frequency combs for generating entangled photon pairs, as well as multi-photon states, and high-dimensional (D-level, i.e. quDit) entangled photons. In particular, we manage to coherently manipulate such complex quantum systems by using telecommunications components (standard fiber telecom).
Dynamics of four-wave-mixing oscillators with quasi-phase-matching
2009
The effect of pump-wave misalignment on the oscillation spectra of a semilinear photorefractive oscillator is studied numerically and compared with the results of experiments performed with ${\text{BaTiO}}_{3}:\text{Co}$ and ${\text{KNbO}}_{3}:\text{Ag},\text{Fe}$ crystals.
Quantumness and speedup limit of a qubit under transition frequency modulation
2022
Controlling and maintaining quantum properties of an open quantum system along its evolution is essential for both fundamental and technological aims. We assess the capability of a frequency-modulated qubit embedded in a leaky cavity to exhibit enhancement of its dynamical quantum features. The qubit transition frequency is sinusoidally modulated by an external driving field. We show that a properly optimized quantum witness effectively identifies quantum coherence protection due to frequency modulation while a standard quantum witness fails. We also find an evolution speedup of the qubit through proper manipulation of the modulation parameters of the driving field. Importantly, by introduc…
Sensitive laser spectroscopy on trapped barium ions by quenching with hydrogen
1983
The sensitivity of laser spectroscopy on barium ions stored in a radio frequency quadrupole trap was drastically increased by using hydrogen for quenching the optically pumped metastable states. The attained fluorescence intensity per ion permits the detection of single ions. The method will be applied to environmental studies on actinides.
Constrained-Design of Passive UHF RFID Sensor Antennas
2013
Passive UHF RFID tags may be used, beside labeling, to remotely observe the physical/chemical change of the tagged object, through modulation of their impedance and gain, thus acting as sensor antennas. The design of this new class of devices can be mastered by fully understanding the relationship between communication and sensing with the purpose to balance the maximization of the dynamic range of the response with the stability of the read distance. A new kind of communication/sensing nomogram permits to display both behaviors in a unitary way and to predict their physical limits, as well as to formalize a multi-parameter general-purpose optimization methodology. The procedure is demonstr…
Passive UHF RFID antennas for sensing applications: Principles, methods, and classifcations
2013
UHF passive radio-frequency identification technology is rapidly evolving from simple labeling of things to wireless pervasive sensing. A remarkable number of scientific papers demonstrate that objects in principle can have their physical properties be remotely tracked and monitored all along their life cycle. The key background is a new paradigm of antenna design that merges together the conventional communication issues with more-specific requirements about sensitivity to time-varying boundary conditions. This paper presents a unified review of the state of the art of the tag-as-sensor problem. Particular care is taken to formalize the measurement indicators and the communication and sens…
Pervasive body sensing: Implanted RFID tags for vascular monitoring
2010
Beside the common logistic usages of the Radio Frequency Identification (RFID) technology, one of the most innovative and promising applications is the possibility to process the backscattering signals to detect additional information about the target, such as its state and its evolution, without any specific embedded sensor or local power supply. The rationale of this idea lies in the clear dependence of the tag's input impedance and reflectivity on the physical and geometrical features of a real target. When the object where the tag is attached on undergoes some changes along with the time, the tag's electrical features also change and these variations can be remotely detected by the read…
Implementation of Universal Digital Architecture using 3D-NoC for Mobile Terminal
2014
International Conference on Control, Decision and Information Technologies (CoDIT), Ecole Natl Ingenieurs Metz, Metz, FRANCE, NOV 03-05, 2014; International audience; The need to integrate multiple wireless communication protocols into a single low-cost flexible hardware platform is prompted by the increasing number of emerging communication protocols and applications in modern embedded systems. So the current challenge is to design of new digital architectures, in addition to its ability to take over of many functions. In this paper we have identified similarities between the despreader units in Rake receiver and the processor element in FFT-SDF (Fast Fourier Transform-Single path Delay Fe…