Beyond Effective Potential via Variational Perturbation Theory
... a system can only be described correctly in the strong-coupling limit, i.e. for large coupling constants, the original weak-coupling series will be completely inadequate to describe the system. In either case, in order for the description of a system to be closed and complete, it must be possible th ...
... a system can only be described correctly in the strong-coupling limit, i.e. for large coupling constants, the original weak-coupling series will be completely inadequate to describe the system. In either case, in order for the description of a system to be closed and complete, it must be possible th ...
High Rydberg states of DABCO: Spectroscopy, ionization potential
... accomplished by setting the bias field to 0.5 V/cm and the time delay between laser excitation and pulsed field ionization/extraction to typically 6 ms. The Rydberg excitation laser is then set in frequency to '5 cm21 above the ionization threshold. Then the reflector voltage is increased until the ...
... accomplished by setting the bias field to 0.5 V/cm and the time delay between laser excitation and pulsed field ionization/extraction to typically 6 ms. The Rydberg excitation laser is then set in frequency to '5 cm21 above the ionization threshold. Then the reflector voltage is increased until the ...
Physics Laboratory and Activity Manual
... Yellow: Key Questions What & When?What needs to be done? When is it due?Personality Strengths People with a strong Mind temperament are responsible, hardworking, and detailed. They provide stability to a project or group. Their willingness to learn, be on time, and keep a project organized is very h ...
... Yellow: Key Questions What & When?What needs to be done? When is it due?Personality Strengths People with a strong Mind temperament are responsible, hardworking, and detailed. They provide stability to a project or group. Their willingness to learn, be on time, and keep a project organized is very h ...
Squeezed light
... (1) the product ∆X 2 ∆P 2 = 1/4 is the same as that for the vacuum state. Squeezing is best visualized by means of the Wigner function — the quantum analogue of the phase-space probability density. Figure 1(c,d) display the Wigner functions of the position- and momentum-squeezed vacuum states, respe ...
... (1) the product ∆X 2 ∆P 2 = 1/4 is the same as that for the vacuum state. Squeezing is best visualized by means of the Wigner function — the quantum analogue of the phase-space probability density. Figure 1(c,d) display the Wigner functions of the position- and momentum-squeezed vacuum states, respe ...
Physics of Projected Wavefunctions
... system with a Mott insulator ground state, since we are doing perturbation about a localized state. In terms of the original Hilbert space, this means that doubly occupied and empty sites are bound [S]. d.c. conductivity is therefore zero, since these excitons of doubly occupied and empty sites are ...
... system with a Mott insulator ground state, since we are doing perturbation about a localized state. In terms of the original Hilbert space, this means that doubly occupied and empty sites are bound [S]. d.c. conductivity is therefore zero, since these excitons of doubly occupied and empty sites are ...
The LPM effect in sequential bremsstrahlung
... To Qualitatively understand the LPM effect, consider an electron scattering multiple times from the medium and radiating a photon. The photon cannot resolve details that are smaller than its wavelength. This will create a region of fuzziness, depicted as the blue shaded region above. We won’t be abl ...
... To Qualitatively understand the LPM effect, consider an electron scattering multiple times from the medium and radiating a photon. The photon cannot resolve details that are smaller than its wavelength. This will create a region of fuzziness, depicted as the blue shaded region above. We won’t be abl ...
Fundamental of Physics
... 16. We determine each capacitance from the slope of the appropriate line in the graph. Thus, C1 = (12 C)/(2.0 V) = 6.0 F. Similarly, C2 = 4.0 F and C3 = 2.0 F. The total equivalent capacitance is C123 = ((C1)1 + (C3 + C2)1)1 = 3.0 F. This implies that the charge on capacitor 1 is (3.0 F)(6. ...
... 16. We determine each capacitance from the slope of the appropriate line in the graph. Thus, C1 = (12 C)/(2.0 V) = 6.0 F. Similarly, C2 = 4.0 F and C3 = 2.0 F. The total equivalent capacitance is C123 = ((C1)1 + (C3 + C2)1)1 = 3.0 F. This implies that the charge on capacitor 1 is (3.0 F)(6. ...
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.