Search results for "Tunnel ionization"

showing 3 items of 3 documents

Piecewise static Hamiltonian for an atom in strong laser field

2009

We show that it is possible to use a piecewise constant Hamiltonian to describe the main features of the dynamics of an atom interacting with a laser field. In particular we show that using this approximation we are able to give a good description of the ionization signal, of the HHG spectra and of the attosecond pulses generated by the radiating electron. Finally, we give an explicit formula to evaluate the ionization rate in the time dependent laser field. This formula, which is a generalization of the Landau formula for the ionization rate of an atom in a static electric field, fairly well reproduces the numerical ionization rates for a broad range of laser frequency and intensity. The m…

Physicscampi laserSettore FIS/02 - Fisica Teorica Modelli E Metodi MatematiciAttosecondPhotoionizationElectronAtomic and Molecular Physics and OpticsSettore FIS/03 - Fisica Della Materiasymbols.namesakeAtom laserTunnel ionizationIonizationPhysics::Atomic and Molecular ClusterssymbolsPiecewiseAtomiPhysics::Atomic PhysicsAtomic physicsHamiltonian (quantum mechanics)
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Direct observation of second-order atom tunnelling

2007

Tunnelling of material particles through a classically impenetrable barrier constitutes one of the hallmark effects of quantum physics. When interactions between the particles compete with their mobility through a tunnel junction, intriguing novel dynamical behaviour can arise where particles do not tunnel independently. In single-electron or Bloch transistors, for example, the tunnelling of an electron or Cooper pair can be enabled or suppressed by the presence of a second charge carrier due to Coulomb blockade. Here we report on the first direct and time-resolved observation of correlated tunnelling of two interacting atoms through a barrier in a double well potential. We show that for we…

Condensed Matter::Quantum GasesJosephson effectQuantum PhysicsMultidisciplinaryCondensed matter physicsChemistryFOS: Physical sciencesCoulomb blockadeCondensed Matter::Mesoscopic Systems and Quantum Hall EffectCondensed Matter - Other Condensed MatterTunnel effectTunnel ionizationUltracold atomTunnel junctionCondensed Matter::SuperconductivityCooper pairQuantum Physics (quant-ph)Quantum tunnellingOther Condensed Matter (cond-mat.other)Nature
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Anomalous properties of hot dense nonequilibrium plasmas

2005

A concise overview of a number of anomalous properties of hot dense nonequilibrium plasmas is given. The possibility of quasistationary megagauss magnetic field generation due to Weibel instability is discussed for plasmas created in atom tunnel ionization. The collisionless absorption and reflection of a test electromagnetic wave normally impinging on the plasma with two-temperature bi-maxwellian electron velocity distribution function are studied. Due to the wave magnetic field influence on the electron kinetics in the skin layer the wave absorption and reflection significantly depend on the degree of the electron temperature anisotropy. The linearly polarized impinging wave during reflec…

PhysicsHistoryElectronPlasmaElliptical polarizationElectromagnetic radiationComputer Science ApplicationsEducationWeibel instabilityTunnel ionizationPhysics::Plasma PhysicsIonizationElectromagnetic electron waveAtomic physics
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