scholarly journals Determination of the effective transverse coherence of the neutron wave packet as employed in reflectivity investigations of condensed-matter structures. I. Measurements

2014 ◽  
Vol 89 (3) ◽  
Author(s):  
Charles F. Majkrzak ◽  
Christopher Metting ◽  
Brian B. Maranville ◽  
Joseph A. Dura ◽  
Sushil Satija ◽  
...  
Keyword(s):  
Wave Packet ◽  
Condensed Matter ◽  
Neutron Wave

SIMULATION PROCEDURES IN CONDENSED MATTER PHYSICS: AN ALGORITHM ALTERNATIVE TO THE STANDARD RANDOM NUMBER GENERATORS

1994 ◽  
Vol 08 (19) ◽  
pp. 1163-1173
Author(s):  
ALESSANDRO CORDELLI
Keyword(s):  
Random Number ◽  
Condensed Matter ◽  
Vibrational Structure ◽  
Periodic Systems ◽  
Solid State Physics ◽  
Random Number Generators ◽  
Simulation Techniques ◽  
Random Hamiltonian ◽  
Better Than

Numerical simulation techniques play a very important role in solid state physics, in particular, as far as the determination of electronic and vibrational structure of non-periodic systems is concerned. The basis of these techniques is the construction of a random Hamiltonian and a random state of interest; to do that, standard congruential algorithms for the generation of pseudorandom numbers are commonly used. The aim of this paper is to propose a novel, alternative way for the generation of random operators and vectors. This technique, based on the concept of minimum correlation sequence, gives results equivalent to or better than the standard approach.

scholarly journals High Temperature Resonant Ultrasound Spectroscopy: A Review

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
G. Li ◽  
J. R. Gladden
Keyword(s):  
High Temperature ◽  
Elastic Constants ◽  
Resonance Spectrum ◽  
Condensed Matter ◽  
Amorphous Solid ◽  
Theoretical Background ◽  
Resonant Ultrasound Spectroscopy ◽  
Other Information ◽  
Resonant Ultrasound

The measurement of elastic constants plays an important role in condensed matter physics and materials characterization. This paper presents the resonant ultrasound spectroscopy (RUS) method for the determination of elastic constants in a single crystal or amorphous solid. In RUS, the measured resonance spectrum of a properly prepared sample and other information such as geometry, density, and initial estimated elastic constants are used to determine the elastic constants of the material. We briefly present the theoretical background and applications to specific materials; however, the focus of this review is on the technical applications of RUS, especially those for high-temperature measurements.

The gravitational phase-shift of a neutron wave-packet

1987 ◽  
Vol 121 (8-9) ◽  
pp. 381-384 ◽  
Author(s):  
Yoshinaga Takahashi
Keyword(s):  
Phase Shift ◽  
Wave Packet ◽  
Neutron Wave

scholarly journals Determination of wave vectors using the phase differencing method

2013 ◽  
Vol 31 (9) ◽  
pp. 1611-1617 ◽  
Author(s):  
S. N. Walker ◽  
I. Moiseenko
Keyword(s):  
Wave Packet ◽  
Correlation Length ◽  
Coherence Length ◽  
Low Frequency ◽  
Plasma Waves ◽  
Mhd Waves ◽  
Space Plasmas ◽  
The Waves ◽  
Theoretical Results

Abstract. Due to the collisionless nature of space plasmas, plasma waves play an important role in the redistribution of energy between the various particle populations in many regions of geospace. In order to fully comprehend such mechanisms it is necessary to characterise the nature of the waves present. This involves the determination of properties such as wave vector k. There are a number of methods used to calculate k based on the multipoint measurements that are now available. These methods rely on the fact that the same wave packet is simultaneously observed at two or more locations whose separation is small in comparison to the correlation length of the wave packet. This limitation restricts the analysis to low frequency (MHD) waves. In this paper we propose an extension to the phase differencing method to enable the correlation of measurements that were not made simultaneously but differ temporally by a number of wave periods. The method is illustrated using measurements of magnetosonic waves from the Cluster STAFF search coil magnetometer. It is shown that it is possible to identify wave packets whose coherence length is much less than the separation between the measurement locations. The resulting dispersion is found to agree with theoretical results.

Curvature Determination of Spinodal Interface in a Condensed Matter System

1997 ◽  
Vol 78 (11) ◽  
pp. 2248-2251 ◽  
Author(s):  
Hiroshi Jinnai ◽  
Tsuyoshi Koga ◽  
Yukihiro Nishikawa ◽  
Takeji Hashimoto ◽  
Stephen T. Hyde
Keyword(s):  
Condensed Matter ◽  
Condensed Matter System ◽  
Matter System

scholarly journals Equation of State of Warm Condensed Matter

1997 ◽  
Vol 499 ◽  
Author(s):  
T. W. Barbee ◽  
D. A. Young ◽  
F. J. Rogers
Keyword(s):  
Equation Of State ◽  
Finite Temperature ◽  
Condensed Matter ◽  
Accurate Determination ◽  
Temperature Limit ◽  
High Temperature Limit ◽  
Condensed Matter Theory ◽  
Matter Theory ◽  
Properties Of Materials

ABSTRACTRecent advances in computational condensed matter theory have yielded accurate calculations of properties of materials. These calculations have, for the most part, focused on the low temperature (T=0) limit. An accurate determination of the equation of state (EOS) at finite temperature also requires knowledge of the behavior of the electron and ion thermal pressure as a function of T. Current approaches often interpolate between calculated T=0 results and approximations valid in the high T limit. Plasma physics-based approaches are accurate in the high temperature limit, but lose accuracy below T∼Tfermi. We seek to “connect up” these two regimes by using ab initio finite temperature methods (including linear-response[l] based phonon calculations) to derive an equation of state of condensed matter for T<Tfermi.We will present theoretical results for the principal Hugoniot of shocked materials, including carbon and aluminum, up to pressures P>100 GPa and temperatures T> 104K, and compare our results with available experimental data.

scholarly journals OPTIMIZATION OF A VIBRATING SAMPLE MAGNETOMETER FOR A LABORATORY PHYSICS COURSE

2017 ◽  
Vol 26 (2) ◽  
pp. 27 ◽  
Author(s):  
Félix L. Avilés ◽  
Elmer Monteblanco ◽  
Abel Gutarra
Keyword(s):  
Condensed Matter ◽  
Oscillation Amplitude ◽  
Real Problem ◽  
Vibrating Sample Magnetometer ◽  
Induced Voltage ◽  
Frequency Oscillation ◽  
Palabras Clave ◽  
The One ◽  
Physics Course

ABSTRACTThis paper describes the implementation and a detailed optimization of a Vibrating Sample Magnetometer (VSM) for an undergraduate physics course laboratory. The VSM operation parameters were extensively discussed using Foner and Mallison coils configuration. The influence of the involved parameters (e.g. oscillation frequency, oscillation amplitude, rate change of the external magnetic field, coils configuration, etc.) on the induced voltage in the pick-up coils were discussed. A disk of nickel of 6-mm diameter was used for the calibration of the magnetometer, comparing the hysteresis loop measured with our magnetometer with the one obtained using a commercial VSM. Magnetization curves of two different samples were obtained in order to test the sensitivity of the magnetometer. The vibrating sample magnetometer implemented in the present work is able to detect changes in the total magnetic moment down to 10-3 emu. The detailed optimization of the VSM described in the present work is an example of how to solve a real problem in condensed matter, related to the determination of the magnetization value of a magnetic sample. Keywords.- : Vibrating sample magnetometer, Magnetometry, Instrumentation. RESUMEN Este artículo describe la implementación y una optimización detallada de un magnetómetro de muestra vibrante (VSM) para un laboratorio de licenciatura en física. Los parámetros de operación de VSM se discutieron ampliamente usando la configuración de bobinas de Foner y Mallison. Se discutió la influencia de los parámetros implicados (por ejemplo, frecuencia de oscilación, amplitud de oscilación, cambio de velocidad del campo magnético externo, configuración de bobinas, etc.) sobre la tensión inducida en las bobinas de captación. Se utilizó un disco de níquel de 6 mm de diámetro para la calibración del magnetómetro, comparando el bucle de histéresis medido con nuestro magnetómetro con el obtenido utilizando un VSM comercial. Se obtuvieron curvas de magnetización de dos muestras diferentes para probar la sensibilidad del magnetómetro. El magnetómetro de muestra vibrante implementado en el presente trabajo es capaz de detectar cambios en el momento magnético total hasta 10-3 emu. La optimización detallada del VSM descrita en el presente trabajo es un ejemplo de cómo resolver un problema real en materia condensada, relacionado con la determinación del valor de magnetización de una muestra magnética. Palabras clave.-Magnetómetro de muestra vibrante, Magnetometría, Instrumentación,

Fluorescence‐detected wave packet interferometry. II. Role of rotations and determination of the susceptibility

1992 ◽  
Vol 96 (6) ◽  
pp. 4180-4194 ◽  
Author(s):  
N. F. Scherer ◽  
A. Matro ◽  
L. D. Ziegler ◽  
M. Du ◽  
R. J. Carlson ◽  
...  
Keyword(s):  
Wave Packet
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