Einstein's Photon Research Articles

'Seeing with one's own eyes' and speaking to the mind: a history of the Wilson cloud chamber in the teaching of physics.

In 1911 the Wilson cloud chamber opened new possibilities for physics pedagogy. The instrument, which visualized particles' tracks as trails of condensed vapour, was adopted by physicists to pursue frontier research on the Compton effect, the positron and the transmutation of atomic nuclei. But as the present paper will show, Wilson's instrument did not just open up new research opportunities, but the possibility of developing a different kind of teaching. Equipped with a powerful visualization tool, some physicists-teachers employed Wilson's instrument to introduce their students to a wide range of phenomena and concepts, ranging from the behaviour of clouds to Einstein's photon, the wave-particle duality and the understanding of the nucleus. This paper uses the notes, books and prototypes of these pioneering physicists-teachers to compose a pedagogical history of the Wilson cloud chamber, documenting an episode of immense ingenuity, creativity and scientific imagination.

How to understand the tunneling in attosecond experiment?: Bohr–Einstein photon box Gedanken experiment, tunneling time and the wave particle duality

The measurement of the tunneling time (T-time) in today’s attosecond and strong field (low-frequency) experiments, despite its controversial discussion, offers a fruitful opportunity to understand time measurement and the time in quantum mechanics. In addition, as we will see in this work, a related controversial issue is the particulate nature of the radiation. The T-time in attosecond experiment and its different aspects and models, is discussed in this work, especially in relation to my model of real T-time (Kullie, 2015), where a good agreement with the experiment and an intriguing similarity to the Bohr–Einstein photon box Gedanken experiment was found. The tunneling process itself is still not well understood, but I am arguing that a scattering mechanism (by the laser wave packet) offers a possibility to understand the tunneling process in the tunneling region. This is related to the question about the corpuscular nature of light which is widely discussed in modern quantum optics experiments.

Lossless and Sufficient $\Psi$ -Invariant Decomposition of Random Reciprocal Target

The target coherency or covariance matrices are the main operators useful for characterizing the polarization transformation properties of radar target by modeling the depolarization effect. In this paper, a novel decomposition of the target coherency matrix is proposed, that is sufficient for representing the physical characteristics of the observed medium in term of a minimum set of orientation invariant parameters. The Einstein's photon circular polarization basis is used for obtaining an orientation invariant physical interpretation of the proposed parameter set both for deterministic and random target. A generalized unsupervised classification scheme is also proposed for underlining the effectiveness of the proposed decomposition theorem for classifying random reciprocal target into 75 physically meaningful clusters. The application of the proposed decomposition theorem and classification algorithm is useful for developing of novel Remote Sensing products and Data Mining softwares for monitoring the surfaces of the Earth and the Moon.

Electromagnetically induced transparency with variable fluctuation time of photon number of pseudothermal probe light

We investigate the electromagnetically induced transparency (EIT) in Rb atoms interacting with a pseudothermal probe light exhibiting a Bose–Einstein photon number distribution. The EIT spectrum in the 5S1/2−5P1/2 transition of the Λ-type system of the 87Rb atom was observed using a coupling laser and the pseudothermal probe light generated by passing the probe laser though a rotating rough disk. From the EIT spectrum with pseudothermal light, we experimentally demonstrated that the fluctuation of the number of photons was the same as the superposition of frequency noise of the probe light. The coherence time of the pseudothermal probe light was estimated from the measured EIT spectra. We confirmed that the experimental results as a function of the rotating speed of the rough disk were in good agreement with the numerically calculated results.

Symplectic geometry of Maxwell theory and the photon concept

For an arbitrary multiply connected cavity a solution theory for the Maxwell equations is developed under ideal conductor boundary conditions. The trajectories of the electromagnetic fields are decomposed into their Helmholtz–Hodge components, including so–called cohomological fields which correspond to the harmonic differential forms. A canonical formalism is formulated in the Coulomb gauge, which comprises only the transversal and cohomological components. The canonical vector potentials and their conjugate fields are smeared in terms of smooth test functions. The Poisson bracket for the smeared fields is based on a symplectic form in the test function space and the corresponding infinite dimensional symplectic Lie algebra is introduced. The conservation quantities of Maxwell theory arise in this manner as co–momentum images of the Lie algebra. By means of a symplectic transformation the transversal dynamical generator is diagonalized and defines a special complexification of the test function space. A diagonalization of the cohomological dynamical generator is proved impossible.Since the Weyl quantization provides a symplectic equivariant map of the classical fields onto the quantum fields (affiliated with our C*–Weyl algebra), we have in quantum electrodynamics the same freedom of symplectic transformations and complexifications in the test function space (and not in the representing Hilbert space). Using the diagonalizing complexification we introduce the (smeared) transversal creation and annihilation operators and arrive at a unique particle structure for the transversal fields in a Fock representation. The symplectic Lie algebra elements, multiplied by iℏ, constitute the one–photon observables, where especially the diagonal dynamical Maxwell generator generalizes Einstein's photon energy to our general set up. The quantum co–momentum map acquires the form of a second quantization of the one-photon observables and leads to particle conserving multi–photon Hamiltonians for the complex linear Lie algebra elements, whereas the anti-linear Lie algebra elements generate particle non–conserving squeezing Hamiltonians. Since there is no particle structure for the quantized cohomological fields their collective nature is confirmed, illustrating the difference between quantization and particle discretization.

Lord Rutherford of Nelson, his 1908 Nobel Prize in Chemistry, and why he didn't get a second prize

‘I have dealt with many different transformations with various periods of time, but the quickest that I have met was my own transformation in one moment from a physicist to a chemist.’Ernest Rutherford (Nobel Banquet, 1908)This article is about how Ernest Rutherford (1871-1937) got the 1908 Nobel Prize in Chemistry and why he did not get a second Prize for his subsequent outstanding discoveries in physics, specially the discovery of the atomic nucleus and the proton. Who were those who nominated him and who did he nominate for the Nobel Prizes? In order to put the Prize issue into its proper context, I will briefly describe Rutherford's whereabouts.Rutherford, an exceptionally gifted scientist who revolutionized chemistry and physics, was moulded in the finest classical tradition. What were his opinions on some scientific issues such as Einstein's photon, uncertainty relations and the future prospects for atomic energy? What would he have said about the ‘Theory of Everything’?Extended version of an invited talk presented at the conference ‘Neutrino 2008’, Christchurch, NZ, 25-31 May 2008

Complementarity in the Einstein–Bohr photon box

The Bohr–Einstein photon box thought experiment is a forerunner of the EPR experiment: a packet of radiation escapes from a box, and the box-plus-radiation state remains entangled. Hence, a measurement on the box makes a difference for the state of the far-away radiation long after its escape. This consequence is analogous to the EPR experiment, but an additional aspect of the Bohr–Einstein box is that complementary magnitudes of the escaped radiation seem correlated to jointly measurable box quantities, which appears to imply a violation of the uncertainty relations. We show how the details of the dynamics make this latter paradox disappear. This calculation makes Bohr’s qualitative arguments in defense of the uncertainty relations precise and reinforces the EPR-like behavior that Einstein later claimed to have had in mind. The calculation reveals that the quantum description of the far-away radiation depends on exactly when the box measurement is performed.

Bose–Einstein photon correlations in the stochastic interferometer

We describe a nonstationary field interferometer, a device for measuring interference among particle Feynman paths that arise from an externally driven stochastic scattering process. Bose-Einstein photon correlations are found to arise from a uniform distribution of the driving noise. A quantum visibility theory valid for any excitation noise distribution is given. The results are considered from the perspective of the probability theory and of statistical mechanics.

Quantum derivation of K-distributed noise for finite 〈N〉

Semiclassical derivations of the fluctuations of light beams have relied on limiting procedures in which the average number, 〈N〉, of scattering elements, photons, or superposed wave packets approaches infinity. We show that the fluctuations of thermal light having a Bose–Einstein photon distribution and of light with an amplitude distribution based on the modified Bessel functions, Kα−1, which has been found useful in describing light scattered from or through turbulent media, may be derived with a quantum-mechanical analysis as the superposition of a random number, N, of single-photon eigenstates with finite 〈N〉. The analysis also provides the P representation for K-distributed noise. Generalizations of K noise are proposed. The factor-of-2 increase in the photon-number second factorial moment related to photon clumping in the Hanbury Brown–Twiss effect for thermal (Gaussian) fields is shown to arise generally in these random superposition models, even for non-Gaussian fields.