Top PDF The quantum electrodynamics of a medium

The quantum electrodynamics of a medium

The quantum electrodynamics of a medium

The incident free particle of energy E interacts with the atomic electrons losing energy w after which it is a free particle of energy E - wand momentum given by the law of conservation [r]

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Casimir effect from macroscopic quantum electrodynamics

Casimir effect from macroscopic quantum electrodynamics

theoretical basis of the Casimir effect should therefore be a quantum theory of Maxwell’s macroscopic electromagnetism. But whereas the quantum theory of the free-space Maxwell equations, QED, was the foundation of quantum field theory, and led to a general formalism for quantizing classical field theories, this quantization procedure was not applied to macroscopic electromagnetism. What has become known in the literature as macroscopic QED is not based on the rules for quantizing field theories, but is instead a phenomenological theory wherein no rigorous quantization is attempted (see [7, 8] for detailed presentations). This phenomenological procedure is subject to much of the criticism directed at Lifshitz theory, and it will be seen that the results derived in this paper require, among other things, an action principle, something that is lacking in the phenomenological approach. The quantization rules of quantum field theory were not obviously applicable in the case of macroscopic electromagnetism due to the complications of dispersion and dissipation, and this is what led to the phenomenological approach. In fact, it had been ‘widely agreed’ [9] that a proper quantization of macroscopic electromagnetism could not be performed, and that only in cases where a simple microscopic model of the dielectric functions of the medium is explicitly introduced could the standard quantization rules be applied. In [10], however, the canonical quantization of macroscopic electromagnetism was achieved, providing a rigorous macroscopic QED and removing the need for a phenomenological approach. Since the macroscopic QED derived in [10] applies to arbitrary magnetodielectrics and takes full account of dispersion and absorption, it meets the criteria outlined above for a rigorous quantum foundation for the Casimir effect. This paper derives the Casimir effect from macroscopic QED by considering the special case of thermal equilibrium 1 .
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Helmer, Ferdinand
  

(2009):


	Quantum information processing and measurement in circuit quantum electrodynamics.


Dissertation, LMU München: Fakultät für Physik

Helmer, Ferdinand (2009): Quantum information processing and measurement in circuit quantum electrodynamics. Dissertation, LMU München: Fakultät für Physik

Before we turn to a description of our proposal, we note that experiments right now are ob- viously still struggling to improve the fidelity of single- and two-qubit operations for super- conducting qubits, and this painstaking work is crucial for further progress in the whole field. Nevertheless, the effort going into this endaveour is ultimately justified by the long-term goal of implementing large-scale circuits able to perform nontrivial quantum computation tasks, where the numbers of qubits may run into the thousands. While present-day experiments are still very far from this goal, it is worthwile to develop architectures that couple more than a handful of qubits in a nontrivial setup, and which represent a challenging medium term goal for the experiments to strive for. We will demonstrate that parameters (dephasing times, coupling strengths etc.) near those that are available nowadays would allow for a first proof- of-principle experiment in our proposed architecture, and further progress in the perfection of single qubits will enable truly useful larger scale versions. The basic ideas behind our scheme are sufficiently general so as to permit replacing individual building blocks (partic- ular qubit types, two-qubit gates etc.) by improved versions that might be developed within the coming years.
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Dynamical evolution of nonclassical properties in cavity quantum electrodynamics with a single trapped ion

Dynamical evolution of nonclassical properties in cavity quantum electrodynamics with a single trapped ion

A semiclassical model describing the dynamics of trapped ions interacting with a traveling-wave light field was introduced by Blockley et al. [12]. An analogous model employing standing-wave light fields was proposed by Cirac et al. [13]-[14]. In these models a single two-level ion undergoes quantized vibrational motion within a harmonic trapping potential and interacts with a classical single-mode light field. It was found [12] that in the Lamb- Dicke regime the dynamics of trapped ion can be described by a very simple Hamiltonian similar to that of the Jaynes- Cummings model [15]. Later it was shown that beyond the Lamb-Dicke regime the vibrational motion of a trapped ion can be described by a strongly nonlinear Jaynes-Cummings model [16]-[18]. Within the framework of these Jaynes- Cummings-like models, various aspects of the dynamics of trapped ions have been studied. For example, quantum nondemolition measurement of vibrational quanta of trapped ions has been analyzed theoretically [19] and several schemes proposed for generating nonclassical motional states of trapped ions, such as Fock states [20]- [21], squeezed state [22]-[24], even and odd coherent
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Introduction to Electrodynamics (2)

Introduction to Electrodynamics (2)

In the integral form of  W , is the total potential at , due to the rest of the charge dist plus the charge at .  For a truly continuous charge dist, this is the same as the    due to t[r]

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Electrodynamics and time orientability

Electrodynamics and time orientability

Aspects of this argument are well known and usually described as a Dirac monopole [1]. It is worthwhile to distinguish the arguments. A key difference is the origin of the U(1) bundle: In this paper it arises naturally and inescapably from the geometry and non time orientability. In earlier works the U(1) bundle is related to the phase of the quantum mechan- ical wavefunction - quantum theory and some aspects of quantisation are assumed at the outset. In contrast, this paper is entirely classical and is unique in deriving both Maxwell like equations and quantised charges without invoking quantum theory. A common treat- ment of the Dirac monopole is to consider geodesically incomplete manifolds (by removing a point at the origin of R 3 ), In this paper spacetime is geodesically complete and space is
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Laser opacity in underdense preplasma of solid targets due to quantum electrodynamics effects

Laser opacity in underdense preplasma of solid targets due to quantum electrodynamics effects

We investigate how next-generation laser pulses at 10–200 PW interact with a solid target in the presence of a relativistically underdense preplasma produced by amplified spontaneous emission (ASE). Laser hole boring and relativistic transparency are strongly restrained due to the generation of electron-positron pairs and γ-ray photons via quantum electrodynamics (QED) processes. A pair plasma with a density above the initial preplasma density is formed, counteracting the electron-free channel produced by hole boring. This pair-dominated plasma can block laser transport and trigger an avalanchelike QED cascade, efficiently transferring the laser energy to the photons. This renders a 1-μm scale-length, underdense preplasma completely opaque to laser pulses at this power level. The QED-induced opacity therefore sets much higher contrast requirements for such a pulse in solid-target experiments than expected by classical plasma physics. Our simulations show, for example, that proton acceleration from the rear of a solid with a preplasma would be strongly impaired.
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An Analysis of Circulation of Decentralized Digital Money in Quantum Electrodynamics Space: the Econphysics Approach

An Analysis of Circulation of Decentralized Digital Money in Quantum Electrodynamics Space: the Econphysics Approach

The study aimed at showing how to create and release cryptocurrency, based on which one can introduce a new generation of this money that can continue its life in the quantum computers space and study whether cryptocurrency could be controlled or the rules should be rewritten in line with new technology. Regarding this, we showed the evolution of money and its uses in economic relations. According to the theoretical basics, the concepts, principles and rules of quantum theory in the physics economics were distributed and the use of modern money by simplified electrodynamic patterns of Richard Feynman was shown. The result showed that the subject could be tested through the physics if the system is closed, and due to the limited nature of the creation of cryptocurrencies like bitcoin, with such conditions, this currency can supply the borderless economics with a new approach with infinite probabilities in the quantum paradigm. Furthermore, given the structure of cryptocurrencies, one cannot control them completely controlled and it is better to rewrite the rules for the creation, release and uses of cryptocurrencies
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Electromagnetically Induced Transparency Using a  Artificial Molecule in Circuit Quantum Electrodynamics

Electromagnetically Induced Transparency Using a Artificial Molecule in Circuit Quantum Electrodynamics

Circuit quantum electrodynamics(QED) [7,8], where transmission line resonator plays the role of cavity and superconducting qubit [9,10] behaves as artificial atom to replace the natural atom, has recently become a new test- bed for quantum optics. Compared with the conventional cavity QED with atomic gases, superconducting circuits as artificial quantum systems in solid-state devices have significant advantages, such as offering long coherence time to implement the quantum gate operations [11], huge tunability and controllability by external electromagnetic fields [12]. As an on-chip realization of cavity QED, circuit QED has reproduced many quantum optical phenomena, including Kerr and cross-Kerr nonlinearities [12,13], the Mollow Triplet [14], Autler-Townes effect [15], EIT [16, 17]. Further- more, circuit QED can be used to realize
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Interrelations between Mathematics and Experiment in the Present Structure of Quantum Electrodynamics

Interrelations between Mathematics and Experiment in the Present Structure of Quantum Electrodynamics

Let us examine what experiment says about some fundamental properties of electromagnetic fields. The first is- sue is the difference between bound fields and radiation fields. Let us take the hydrogen atom, which is a quite simple system of a proton and an electron, and use it as our experimental device. It is well known that quantum mechanics provides an extremely successful description of the hydrogen atom. Therefore, the required experi- mental data can be readily taken from quantum mechanics textbooks [13] [14].

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General Classical Electrodynamics

General Classical Electrodynamics

The unfounded conjecture from Quantum Mechanics the- ory: ”the linearly dependent ’scalar’ photon and ’longitudi- nal’ photon do not contribute to field observables”, is obvi- ously based on the false Lorentz premise, and is expressed classically as follows: B = B ∗ = 0. The indeterminacy of the quantum wave function, ψ, is tied to the indeterminacy of the MCED potentials, Φ and A. A gauge transform of the relativistic quantum wave equation is a transformation of the MCED potentials and the quantum wave function in Φ 0 , A 0 and ψ 0 , such that the phase of the transformed function ψ 0 differs a constant with the phase of the function ψ, and such that the relativistic quantum wave equation is ”gauge in- variant” [42]. This means the function ψ is ’unphysical’ and indeterminate as well. The indeterminacy of ψ is explained as ”probabilistic behavior” of elementary particles (the Born rule): the particle velocity is the ψ wave group velocity, and is not associated with ψ wave phase velocity. Gauge invari- ance is also known as gauge symmetry, and is supposed to be the guiding principle of modern particle physics, however, this ”gauge freedom” is merely the consequence of a false Lorentz premise (a = c), that reduces determinate GCED po- tentials to indeterminate MCED potentials. Recent scanning tunneling microscope experiments [43] falsify Heisenberg’s uncertainty relations by close two orders of magnitude, which is proof for the deterministic physical nature of the quantum wave function. The determinate potentials of GCED-WP are agreeable with a determinate quantum wave function, where the phase of ψ has physical meaning. The De Broglie-Bohm pilot wave theory comes into mind, in order to reinterpret quantum entanglement behavior as interferences of physical pilot waves. The unknown nature of Bohm’s pilot wave has been an objection against pilot wave theory, ever since Bohm and de Broglie offered his interpretation Schr¨odinger’s equa- tion solutions. Caroline H. Thompson [44] published a pa- per on the universal ψ function as the Φ-wave aether. In- deed, super luminal Φ-wave fields, acting as particle pilot waves, is a natural suggestion, such that the pilot wave na- ture is no longer ”ghost like” and unknown. Quantum non- locality and non-causal entanglement may be confused with causal and local quasi dynamics. GCED-WP offers a classi- cal foundation for the elementary particle-wave duality. The
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Deterministic amplification of Schrödinger cat states in circuit quantum electrodynamics

Deterministic amplification of Schrödinger cat states in circuit quantum electrodynamics

Quantum physics does not allow perfect deterministic amplification of unknown quantum states because additional quantum noise is inevitably introduced by the ampli fi cation process [ 13 ] . The most commonly studied methods of high fidelity amplification of coherent states (i.e. ∣ a ñ  ∣ G a ñ for G > 1 ) are based on probabilistic addition and subtraction of single photons [14]. The fidelity and amplification factor G of these processes vary differently with input amplitude α , depending on the ampli fi cation operator that is implemented [15–17]. For example, the probabilistic amplification operators aa ˆ ˆ † and ( ˆ ) a † 2 have recently been investigated
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Viehmann, Oliver
  

(2013):


	Multi-qubit circuit quantum electrodynamics.


Dissertation, LMU München: Fakultät für Physik

Viehmann, Oliver (2013): Multi-qubit circuit quantum electrodynamics. Dissertation, LMU München: Fakultät für Physik

controlled interactions between the internal states of the ions. According to the groundbreaking proposal by Cirac and Zoller (1995), the motional sidebands of an individual ion can be exter- nally driven to map the internal state of the ion to a collective vibrational state. Conditioned on the vibrational state, a second ion the trap is excited or not. The entangling part in this ex- citation consists in adding a sign to only one of the product states of collective motion and the spin of the second ion. To do so, this one state is selectively cycled through an auxiliary state. If after the conditional excitation of the second ion the motional state is swapped back to the first ion, one ends up with a CNOT gate between the two ions, which was first implemented by Schmidt-Kaler et al. (2003). Simpler techniques to obtain such interactions, ideally suited for simulating spin Hamiltonians (Porras and Cirac, 2004), involve simultaneous driving of the ions with two tones (Sørensen and Mølmer, 1999). Based on this, two spins with an (adiabat- ically) variable Ising coupling in a transverse field were simulated by Friedenauer et al. (2008) (in the sense of an analog quantum simulation). In a similar experiment with up to nine ions and long-range Ising coupling, Islam et al. (2011) were able to observe the precursors of a quantum phase transition from paramagnetic to ferromagnetic. Gerritsma et al. (2010) simulated the one- dimensional free Dirac equation and were able to observe Zitterbewegung. The two-component spinor was encoded in two internal levels of an ion and the ion’s motional state. In a subsequent work, Gerritsma et al. (2011) included various scattering potentials for the Dirac particle in their quantum simulation, which allowed them to study Klein tunneling. An interacting spin system of potentially computational relevant scale was recently simulated by Britton et al. (2012). The authors used a Penning trap to create a two-dimensional Coulomb crystal of about 300 ions. Again, by coupling the internal states of the ions simultaneously to collective vibrational modes of the ion crystal, both ferromagnetic and anti-ferromagnetic Ising coupling of tunable range could be demonstrated. With improvements in the read-out and the implementation of a compet- ing term in the Hamiltonian, this approach is highly promising for analog quantum simulations. Digital quantum simulations with trapped ions were impressively demonstrated by Lanyon et al. (2011). To simulate, for instance, the time evolution of a two-qubit state under the Hamiltonian
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ON THE AXIOMATIC STRUCTURE OF HERTZIAN ELECTRODYNAMICS

ON THE AXIOMATIC STRUCTURE OF HERTZIAN ELECTRODYNAMICS

While frame indifferent and form invariant electromagnetic field theories, as two al- ternative worldviews and mathematical formulations in describing physical phenomena, were meant to be equally respected on a theoretical ground, 20 th century has experienced an ideological consensus in adopting form invariance as the mainstream physics, where theoretical works that contradict the accepted “physical facts” are largely avoided by “respected” journals and contrary experimental evidences are disregarded. This under- standing is still dominant since “dissident works” –even today– are accepted only by a few indexed journals and rather heavily by nonindexed but openminded ones as Galilean Electrodynamics and Apeiron 7 .
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Electrodynamics in Noninertial Reference Frames

Electrodynamics in Noninertial Reference Frames

A continuous medium in the four-space-time is described by the following characteristics: the four-accelera- tion, the strain-rate tensor, and the tensor of angular velocity of rotation. The four-acceleration enters the motion law, and, with a known flat metric, integration of the motion equation yields the four-velocity field and the fun- damental tensors of the medium. For the frames of reference with properties specified by physical requirements, one must know additional conditions imposed on the fundamental tensors of the medium, which depend on four-velocities and four-accelerations. An example is the requirements to the rotation and rigidity. The number of equations for determining the four-velocity is over determined; therefore, the integrability conditions must be satisfied. This will held true if not only the four-velocities of the medium but also the metric coefficients are de- sired values.
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Electrodynamics in a Strong Magnetic Field

Electrodynamics in a Strong Magnetic Field

mass-shell, it gives the index of refraction of the strong-field region, which is then evaluated numerically and plotted. This makes it possible for photon-splittin[r]

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Quantum Schrödinger String Theory For Frictional Medium & Collision

Quantum Schrödinger String Theory For Frictional Medium & Collision

The quantum equation derived from Max Wells equation for decaying wave in a resistive medium is more advanced than ordinary schord Eqn. This is since it reduces to sch. eqn. It also gives expression for collision probability similar to that obtained by transport Eqn. It also predicts quantized frictional energy.

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A quantum electrodynamics model for non-thermal emission from soft gamma repeaters and anomalous X-ray pulsars

A quantum electrodynamics model for non-thermal emission from soft gamma repeaters and anomalous X-ray pulsars

Observations of the AXPs and SGRs continue to surprise, as do theoretical investigations of ultramagnetized neutron stars. In this paper and Paper I we have presented a unified model for the thermal burst emission and non-thermal emission from ultramagnetized neu- tron stars. The model has few underlying assumptions: magnetars produce fast modes sufficient to power the non-thermal emission and, more rarely, the bursts, the magnetic field far from the star is approximately dipolar, and quantum electrodynamics can account for the dynamics of pairs and photons in strong magnetic fields. The model for the non-thermal emission has two free parameters, a normalization and break frequency. Further observations can easily verify or falsify this model and potentially provide direct evidence for the ultramagnetized neutron stars that power AXPs and SGRs and the macroscopic manifestations of QED processes that account for their unique attributes.
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ON THE ELECTRODYNAMICS OF MOVING BODIES

ON THE ELECTRODYNAMICS OF MOVING BODIES

Examples of this sort, together with the unsuccessful attempts to discover any motion of the earth relatively to the “light medium,” suggest that the phenomena of electrodynamics as well as of mechanics possess no properties corresponding to the idea of absolute rest. They suggest rather that, as has already been shown to the first order of small quantities, the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good. 1 We will raise this conjecture (the purport of

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