16 research outputs found
Long-Range Acoustic Interactions in Insect Swarms: An Adaptive Gravity Model
The collective motion of groups of animals emerges from the net effect of the interactions between individual members of the group. In many cases, such as birds, fish, or ungulates, these interactions are mediated by sensory stimuli that predominantly arise from nearby neighbors. But not all stimuli in animal groups are short range. Here, we consider mating swarms of midges, which are thought to interact primarily via long-range acoustic stimuli. We exploit the similarity in form between the decay of acoustic and gravitational sources to build a model for swarm behavior. By accounting for the adaptive nature of the midges\u27 acoustic sensing, we show that our \u27adaptive gravity\u27 model makes mean-field predictions that agree well with experimental observations of laboratory swarms. Our results highlight the role of sensory mechanisms and interaction range in collective animal behavior. Additionally, the adaptive interactions that we present here open a new class of equations of motion, which may appear in other biological contexts
Long-range Acoustic Interactions in Insect Swarms: An Adaptive Gravity Model
The collective motion of groups of animals emerges from the net effect of the
interactions between individual members of the group. In many cases, such as
birds, fish, or ungulates, these interactions are mediated by sensory stimuli
that predominantly arise from nearby neighbors. But not all stimuli in animal
groups are short range. Here, we consider mating swarms of midges, which
interact primarily via long-range acoustic stimuli. We exploit the similarity
in form between the decay of acoustic and gravitational sources to build a
model for swarm behavior. By accounting for the adaptive nature of the midges'
acoustic sensing, we show that our "adaptive gravity" model makes mean-field
predictions that agree well with experimental observations of laboratory
swarms. Our results highlight the role of sensory mechanisms and interaction
range in collective animal behavior. The adaptive interactions that we present
here open a new class of equations of motion, which may appear in other
biological contexts.Comment: 25 pages, 15 figure
Coherent Excitation of Bound Electron Quantum State With Quantum Electron Wavepackets
We present a fully quantum model for the excitation of a bound electron based on the “free-electron bound-electron resonant interaction” (FEBERI) scheme. The bound electron is modeled as a quantum two-level system (TLS) at any initial quantum (qubit) state, and the free electron is presented as a pre-shaped quantum electron wavepacket (QEW). In the case that the QEW is short or modulated at optical frequency, the TLS quantum state may be coherently controlled with multiple modulation-correlated QEWs. For this case, we derive the transition probability of the TLS due to interaction with a multi-particle beam based on an analytical approximate solution of the Schrodinger equation that amounts to using Born’s probabilistic interpretation of the quantum electron wavefunction. We verify the credibility of the analytical model at its validity ranges using a fully quantum density matrix computation procedure. It is shown that the transition probability can grow quadratically with the number of correlated QEWs and exhibit Rabi oscillation. The study indicates a possibility of engineering the quantum state of a TLS by utilizing a beam of shaped QEWs
An analysis of the Brown-Biefeld effect
When a high voltage is applied on an asymmetric capacitor, it experiences a
force acting toward its thinner electrode. This effect is called Brown-Biefeld
effect (BB), after its discoverers Thomas-Townsend Brown and Paul-Alfred
Biefeld. Many theories have been proposed to explain this effect, and many
speculations can be found on the net suggesting the effect is an
antigravitation or a space warp effect. However, in the recent years, more an
more researchers attribute the BB effect to a unicharge ion wind. This work
calculates the levitation force due to ion wind and presents experimental
results which confirm the theoretical results.Comment: 34 pages, 9 figure