arXiv subjects

Sandor Varro

Publications and source records attributed to Sandor Varro.

24 records · Page 2Linked to original sources

arXiv2006

Einstein's fluctuation formula. A historical overview

A historical overview is given on the basic results which appeared by the year 1926 concerning Einstein's fluctuation formula of black-body radiation, in the context of light-quanta and wave-particle duality. On the basis of the original publications (from Planck's derivation of the black-body spectrum and Einstein's introduction of the photons up to the results of Born, Heisenberg and Jordan on the quantization of a continuum) a comparative study is presented on the first line of thoughts that led to the concept of quanta. The nature of the particle-like fluctuations and the wave-like fluctuations are analysed by using several approaches. With the help of the classical probability theory, it is shown that the infinite divisibility of the Bose distribution leads to the new concept of classical poissonian photo-multiplets or to the binary photo-multiplets of fermionic character. As an application, Einstein's fluctuation formula is derived as a sum of fermion type fluctuations of the binary photo-multiplets.

quant-ph↗

arXiv2006

A study on black-body radiation: classical and binary photons

The present study gives a detailed analysis of the black-body radiation based on classical random variables. It is shown that the energy of a mode of a chaotic radiation field (Gauss variable) can be uniquely decomposed into a sum of a discrete variable (Planck variable having the Planck-Bose distribution) and a continuous dark variable (with a truncated exponential distribution of finite support). The Planck variable is decomposed, on one hand, into a sum of binary variables representing the binary photons of energies 2^s*h*nu with s=0,1,2,etc. In this way the black-body radiation can be viewed as a mixture of thermodinamically independent fermion gases. The Planck variable can also be decomposed into a sum of independent Poisson components representing the classical photo-molecules of energies m*h*nu with m=1,2,3,etc. These classical photons have only particle-like fluctuations, on the other hand, the binary photons have wave-particle fluctuations of fermionic character.

quant-ph↗

arXiv2006

Linear and nonlinear absolute phase effects in interactions of ultrashort laser pulses with a metal nano-layer or with a plasma layer

It has been shown that in the scattered radiation, generated by an ultrashort laser pulse impinging on a metal nano-layer, non-oscillatory wake-fields appear with a definite sign. The magnitude of these wake-fields is proportional with the incoming field strength, and a sign of them is governed by the cosine of the carrier-envelope phase difference of the incoming pulse. At relativistic laser intensities the target is considered as a plasma layer in vacuum, produced from a thin foil by a pre-pulse, which is followed by the main high-intensity laser pulse. The nonlinearities stemming from the relativistic kinematics of the surface current density (representing the plasma electrons) lead to the appearance of higher-harmonics in the scattered spectra. In general, the harmonic peaks are down-shited due to the presence of an intensity-dependent factor. Certain regions of these spectra are very sensitive to the variation of the carrier-envelope phase difference. The spectra has a long tail where the heigths of the peaks vary practically within one order of magnitude forming a quasi-continuum. By Fourier synthetising the components from this plateau region attosecond pulses have been obtained.

physics.plasm-ph↗

arXiv2006

Scattering of a few-cycle laser pulse by a plasma layer: the role of the carrier-envelope phase difference at relativistic intensities

The reflection and transmission of a few-cycle Ti:Sa laser pulse iminging on a thin plasma layer have been analysed on the basis of classical electrodynamics. An approximate analytic solution has been given for the coupled Maxwell-Lorentz equations describing the dynamics of the surface current and the composite radiation field. The nonlinearities stemming from the relativistics kinematics of free electrons lead to the appearance of higher-harmonics in the scattered spectra. In our analysis particular attention has been paid to the effect of the carrier-envelope phase difference of the incoming laser pulse. For the fourth harmonic peak we calculated almost 25 percent modulation. In general, the harmonic peaks are down-shifted due to presence of the intensity-dependent factors by an order of 15-65 percent in case of an incoming field of intensity we have discussed. The spectrum of the high-harmonics has a long tail where the heights of the peaks vary within one order of magnitude forming a quasi-continuum. By Fourier synthetising the field components of this plateau region attosecond pulses have been obtained.

physics.plasm-ph↗

arXiv2006

Reflection of a few-cycle laser pulse on a metal nano-layer: generation of phase-dependent wake-fields

The reflection and transmission of a few-cycle femtosecond Ti:Sa laser pulse impinging on a metal nano-layer have been analysed. The thickness of the layer was assumed to be of order of 2-10 nm, and the metallic free electrons were represented by a surface current density distributed at the plane boundary of a dielectric substrate. The target studied this way can be imagined, for instance, as a semi-transparent mirror produced by evapotating a thin aluminum layer on the surface of a glass plate. The exact analytic solution has been given for the system of the coupled Maxwell-Lorentz equations decribing the dynamics of the surface current and the scattered radiation fields. It has been shown that in general a non-oscillatoty frozen-in wake-field appears following the main pulse with an exponential decay and with a definite sign of the electric field. The characteristic time of these wake-fields is inversely proportional with the square of the plasma frequency and with the thickness of the metal nano-layer, and can be larger than the original pulse duration. The magnitude of these wake-fields is proportional with the incoming field strength, and the definite sign of them governed by the cosine of the carrier-envelope phase difference of the incoming ultrashort laser pulse. As a consequence, when we let such a wake-field excite the electrons of a secondary target (say an electron beam, a metal plate or a gas jet), we obtain 100 percent modulation in the electron signal in a given direction, as we vary the carrier-envelope phase difference. This scheeme can perhaps serve as a basis for the construction of a robust linear carrier-envelope phase difference meter.

physics.plasm-ph↗

arXiv2006

Irreducible decomposition of Gaussian distributions and the spectrum of black-body radiation

It is shown that the energy of a mode of a classical chaotic field, following the continuous exponential distribution as a classical random variable, can be uniquely decomposed into a sum of its fractional part and of its integer part. The integer part is a discrete random variable (we call it Planck variable) whose distribution is just the Bose distribution yielding the Planck law of black-body radiation. The fractional part is the dark part (we call is dark variable) with a continuous distribution, which is, of course, not observed in the experiments. It is proved that the Bose distribution is infinitely divisible, and the irreducible decomposition of it is given. The Planck variable can be decomposed into an infinite sum of independent binary random variables representing the binary photons (more accurately photo-molecules or photo-multiplets) of energies 2^s*h*nu with s=0,1,2... . These binary photons follow the Fermi statistics. Consequently, the black-body radiation can be viewed as a mixture of statistically and thermodynamically independent fermion gases consisting of binary photons. The binary photons give a natural tool for the dyadic expansion of arbitrary (but not coherent) ordinary photon excitations. It is shown that the binary photons have wave-particle fluctuations of fermions. These fluctuations combine to give the wave-particle fluctuations of the original bosonic photons expressed by the Einstein fluctuation formula.

quant-ph↗