3,200 research outputs found
Organic farming and resource efficiency
The Chapter discusses the efficiency of nutrient and energy use in organic farming, regarding the pressing need to make efficient use of natural resources. Nutrient recycling, the use of adapted plant varieties and energy-saving through the ban of synthetic nitrogen fertilizer are organic farming practices that enhance resource efficiency
Thermodynamics of explosions
We present our first attempts to formulate a thermodynamics-like description
of explosions. The motivation is partly a fundamental interest in
non-equilibrium statistical physics, partly the resemblance of an explosion to
the late stages of a heavy-ion collision. We perform numerical simulations on a
microscopic model of interacting billiard-ball like particles, and we analyse
the results of such simulations trying to identify collective variables
describing the degree of equilibrium during the explosion.Comment: 6 pages. Talk presented at "Bologna 2000 - Structure of the nucleus"
international conference, May 29 - June 3, Bologna, Italy. Shortened version,
to appear in the Proceeding
Tomography of a displacement photon counter for discrimination of single-rail optical qubits
We investigate the performance of a Kennedy receiver, which is known as a
beneficial tool in optical coherent communications, to the quantum state
discrimination of the two superpositions of vacuum and single photon states
corresponding to the eigenstates in the single-rail encoding of
photonic qubits. We experimentally characterize the Kennedy receiver in
vacuum-single photon two-dimensional space using quantum detector tomography
and evaluate the achievable discrimination error probability from the
reconstructed measurement operators. We furthermore derive the minimum error
rate obtainable with Gaussian transformations and homodyne detection. Our proof
of principle experiment shows that the Kennedy receiver can achieve a
discrimination error surpassing homodyne detection
Assessments of macroscopicity for quantum optical states
With the slow but constant progress in the coherent control of quantum
systems, it is now possible to create large quantum superpositions. There has
therefore been an increased interest in quantifying any claims of
macroscopicity. We attempt here to motivate three criteria which we believe
should enter in the assessment of macroscopic quantumness: The number of
quantum fluctuation photons, the purity of the states, and the ease with which
the branches making up the state can be distinguished
Super sensitivity and super resolution with quantum teleportation
We propose a method for quantum enhanced phase estimation based on continuous
variable (CV) quantum teleportation. The phase shift probed by a coherent state
can be enhanced by repeatedly teleporting the state back to interact with the
phase shift again using a supply of two-mode squeezed vacuum states. In this
way, both super resolution and super sensitivity can be obtained due to the
coherent addition of the phase shift. The protocol enables Heisenberg limited
sensitivity and super- resolution given sufficiently strong squeezing. The
proposed method could be implemented with current or near-term technology of CV
teleportation.Comment: 5 pagers, 3 figure
Equilibration and freeze-out in an exploding system
We use a simple gas model to study non-equilibrium aspects of the
multiparticle dynamics relevant to heavy ion collisions. By performing
numerical simulations for various initial conditions we identify several
characteristic features of the fast dynamics occurring in implosion-explosion
like processes.Comment: 4 pages, submitted to PR
Teleportation of Nonclassical Wave Packets of light
We report on the experimental quantum teleportation of strongly nonclassical
wave packets of light. To perform this full quantum operation while preserving
and retrieving the fragile non-classicality of the input state, we have
developed a broadband, zero-dispersion teleportation apparatus that works in
conjunction with time-resolved state preparation equipment. Our approach brings
within experimental reach a whole new set of hybrid protocols involving
discrete- and continuous-variable techniques in quantum information processing
for optical sciences
Farmers' organizations in Nnindye, Uganda: building social capital for the conservation of natural resources
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