1,439 research outputs found
Photon temporal modes: a complete framework for quantum information science
Field-orthogonal temporal modes of photonic quantum states provide a new
framework for quantum information science (QIS). They intrinsically span a
high-dimensional Hilbert space and lend themselves to integration into existing
single-mode fiber communication networks. We show that the three main
requirements to construct a valid framework for QIS -- the controlled
generation of resource states, the targeted and highly efficient manipulation
of temporal modes and their efficient detection -- can be fulfilled with
current technology. We suggest implementations of diverse QIS applications
based on this complete set of building blocks.Comment: 17 pages, 13 figure
From quantum pulse gate to quantum pulse shaper -- enigneered frequency conversion in nonlinear optical waveguides
Full control over the spatio-temporal structure of quantum states of light is
an important goal in quantum optics, to generate for instance single-mode
quantum pulses or to encode information on multiple modes, enhancing channel
capacities. Quantum light pulses feature an inherent, rich spectral
broadband-mode structure. In recent years, exploring the use of integrated
optics as well as source-engineering has led to a deep understanding of the
pulse-mode structure of guided quantum states of light. In addition, several
groups have started to investigate the manipulation of quantum states by means
of single-photon frequency conversion. In this paper we explore new routes
towards complete control of the inherent pulse-modes of ultrafast pulsed
quantum states by employing specifically designed nonlinear waveguides with
adapted dispersion properties. Starting from our recently proposed quantum
pulse gate (QPG) we further generalize the concept of spatio-spectral
engineering for arbitrary \chitwo-based quantum processes. We analyse the
sum-frequency generation based QPG and introduce the difference-frequency
generation based quantum pulse shaper (QPS). Together, these versatile and
robust integrated optics devices allow for arbitrary manipulations of the
pulse-mode structure of ultrafast pulsed quantum states. The QPG can be
utilized to select an arbitrary pulse mode from a multimode input state,
whereas the QPS enables the generation of specific pulse modes from an input
wavepacket with Gaussian-shaped spectrum.Comment: 21 pages, 9 figure
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Associations of Partner Support and Acculturation With Physical Activity in Mexican American Women.
IntroductionInsufficient physical activity (PA) and obesity-related health conditions have reached epidemic proportions worldwide. Mexican American women (MAW) report low leisure time physical activity. Few studies examine activities beyond leisure time. Qualitative research suggests that partner support influence provides a cultural approach relevant to PA among MAW.MethodThis cross-sectional study used an ecological model to investigate community (the physical environment), interpersonal (partner support, attitudinal familism), and intrapersonal (age, health conditions, acculturation, employment, and body mass index) factors associated with PA among 112 MAW. Community-based participatory research recommendations guided the preparatory phase of the study and the face-to-face interviews. Frequencies and descriptive statistics were computed. Multivariable linear regression analyses were used to examine associations between study variables.ResultsModerate to high PA levels were found based on combined activities performed during leisure time, transportation, household tasks, and occupational duties. Women with greater partner support reported higher PA levels. Although acculturation levels were low among women, those with higher acculturation were found to be more physically active.ConclusionsFuture studies should examine strategies to increase partner support and address acculturation within intervention programs to enhance overall PA among MAW
Modelling respiration rate of fresh fruits and vegetables for modified atmosphere packages: a review
Respiration rate and gas exchange through the package material are the processes involved in creating a modified atmosphere
inside a package that will extend shelf life of fresh fruits and vegetables. Thus, modelling respiration rate of the selected produce is
crucial to the design of a successful modified atmosphere packaging (MAP) system. In this paper, general aspects of the respiration
process are presented. The major methods for measuring respiration rates, along with their advantages and limitations are discussed.
Factors affecting the respiration rate and respiratory quotient are outlined, stressing the importance of temperature, O2 and CO2
concentrations, and storage time. Respiration rate models in the literature are also reviewed. 2002 Elsevier Science Ltd. All rights
reserved
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