Scheme of work
... teaching of a particular topic, the section dealing with the prior knowledge comes first. Teachers who wish to use the scheme of work as the basis for their courses are likely to use it in one of two ways. One approach is to teach a whole topic at once so that a learner might study only electricity ...
... teaching of a particular topic, the section dealing with the prior knowledge comes first. Teachers who wish to use the scheme of work as the basis for their courses are likely to use it in one of two ways. One approach is to teach a whole topic at once so that a learner might study only electricity ...
Probing Excited-State Electron Transfer by Resonance Stark
... absorption spectrum.1 We recently introduced an approach for analyzing absorption spectra where coupling to intramolecular charge-transfer states is important and applied this method to the electronic absorption line shapes of the heterodimer special pair in bacterial photosynthetic reaction centers ...
... absorption spectrum.1 We recently introduced an approach for analyzing absorption spectra where coupling to intramolecular charge-transfer states is important and applied this method to the electronic absorption line shapes of the heterodimer special pair in bacterial photosynthetic reaction centers ...
Towards a microscopic Description of classical Solutions in Field
... As a next step, we develop the coherent state technique which can be used to represent generic classical fields as bound states. Using this method, we show how we can treat solitons in a microscopic description. In particular, we observe that the stability of the topological soliton can be associate ...
... As a next step, we develop the coherent state technique which can be used to represent generic classical fields as bound states. Using this method, we show how we can treat solitons in a microscopic description. In particular, we observe that the stability of the topological soliton can be associate ...
The Confinement Problem in Lattice Gauge Theory
... First of all, what is quark confinement? The place to begin is with an experimental result: the apparent absence of free quarks in Nature. Free quark searches are basically searches for particles with fractional electric charge [4, 5], and the term “quark confinement” in this context is sometimes eq ...
... First of all, what is quark confinement? The place to begin is with an experimental result: the apparent absence of free quarks in Nature. Free quark searches are basically searches for particles with fractional electric charge [4, 5], and the term “quark confinement” in this context is sometimes eq ...
Modelling the electron and hole states in semiconductor
... The models of the electron and hole states which were developed for the silicon quantum wells were then adopted to compute the electron and hole states in GaAs/(Al,Ga)As quantum wells. The conduction-band states are computed by the effective-mass model, and those results are compared with the result ...
... The models of the electron and hole states which were developed for the silicon quantum wells were then adopted to compute the electron and hole states in GaAs/(Al,Ga)As quantum wells. The conduction-band states are computed by the effective-mass model, and those results are compared with the result ...
Computation of Intrinsic Breakdown Based on Computational
... Figure 1.3(a) Energy balance of a free electron when the electric field is less than the avalanche threshold electric field (FFth).. ...................................... - 8 -
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... Figure 1.3(a) Energy balance of a free electron when the electric field is less than the avalanche threshold electric field (F
Great Neck South High School
... 32. An electron e and a proton p are simultaneously released from rest in a uniform electric field E, as shown above. Assume that the particles are sufficiently far apart so that the only force acting on each particle after it is released is that due to the electric field. At a later time when the p ...
... 32. An electron e and a proton p are simultaneously released from rest in a uniform electric field E, as shown above. Assume that the particles are sufficiently far apart so that the only force acting on each particle after it is released is that due to the electric field. At a later time when the p ...
Physics Mechanics
... If the speeds of the interacting objects are very large, we must replace Classical mechanics with Einstein’s special theory of relativity, which hold at any speed, including those near the speed of light. If the interacting bodies are on the scale of atomic structure, we must replace Classical mecha ...
... If the speeds of the interacting objects are very large, we must replace Classical mechanics with Einstein’s special theory of relativity, which hold at any speed, including those near the speed of light. If the interacting bodies are on the scale of atomic structure, we must replace Classical mecha ...
Casimir effect
In quantum field theory, the Casimir effect and the Casimir–Polder force are physical forces arising from a quantized field. They are named after the Dutch physicist Hendrik Casimir.The typical example is of two uncharged metallic plates in a vacuum, placed a few nanometers apart. In a classical description, the lack of an external field means that there is no field between the plates, and no force would be measured between them. When this field is instead studied using the QED vacuum of quantum electrodynamics, it is seen that the plates do affect the virtual photons which constitute the field, and generate a net force—either an attraction or a repulsion depending on the specific arrangement of the two plates. Although the Casimir effect can be expressed in terms of virtual particles interacting with the objects, it is best described and more easily calculated in terms of the zero-point energy of a quantized field in the intervening space between the objects. This force has been measured and is a striking example of an effect captured formally by second quantization. However, the treatment of boundary conditions in these calculations has led to some controversy.In fact, ""Casimir's original goal was to compute the van der Waals force between polarizable molecules"" of the metallic plates. Thus it can be interpreted without any reference to the zero-point energy (vacuum energy) of quantum fields.Dutch physicists Hendrik B. G. Casimir and Dirk Polder at Philips Research Labs proposed the existence of a force between two polarizable atoms and between such an atom and a conducting plate in 1947, and, after a conversation with Niels Bohr who suggested it had something to do with zero-point energy, Casimir alone formulated the theory predicting a force between neutral conducting plates in 1948; the former is called the Casimir–Polder force while the latter is the Casimir effect in the narrow sense. Predictions of the force were later extended to finite-conductivity metals and dielectrics by Lifshitz and his students, and recent calculations have considered more general geometries. It was not until 1997, however, that a direct experiment, by S. Lamoreaux, described above, quantitatively measured the force (to within 15% of the value predicted by the theory), although previous work [e.g. van Blockland and Overbeek (1978)] had observed the force qualitatively, and indirect validation of the predicted Casimir energy had been made by measuring the thickness of liquid helium films by Sabisky and Anderson in 1972. Subsequent experiments approach an accuracy of a few percent.Because the strength of the force falls off rapidly with distance, it is measurable only when the distance between the objects is extremely small. On a submicron scale, this force becomes so strong that it becomes the dominant force between uncharged conductors. In fact, at separations of 10 nm—about 100 times the typical size of an atom—the Casimir effect produces the equivalent of about 1 atmosphere of pressure (the precise value depending on surface geometry and other factors).In modern theoretical physics, the Casimir effect plays an important role in the chiral bag model of the nucleon; in applied physics, it is significant in some aspects of emerging microtechnologies and nanotechnologies.Any medium supporting oscillations has an analogue of the Casimir effect. For example, beads on a string as well as plates submerged in noisy water or gas illustrate the Casimir force.