Phase Transitions in Solid Methane Up to 60 Kbar

1983 ◽  
Vol 22 ◽  
Author(s):  
N.J. Trappeniers
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Kinetic Energy ◽  
Spherical Shape ◽  
Plastic Crystal ◽  
Cubic Symmetry ◽  
Profound Influence ◽  
Rotational Freedom ◽  
Solid Methane

Solid methane has been a favourite subject for the study of phase transitions ever since the discovery by Clusius [1] of the phase transition α → β at 20.4 K in CH4. The reasons for the sustained interest in solid CH4 may be attributed to the following facts. i. The CH4 molecule has an almost spherical shape with a slight TD anisotropy. As a result, CH4 crystallizes below 90.7 K into a plastic crystal, α, of cubic symmetry, exhibiting almost complete rotational freedom of the molecules. ii. The CH4 molecule is very small in size with a low moment of inertia (I × 1040 g cm2 = 5.34 in CH4 and 10.64 in CD4), leading to a large rotational kinetic energy and related quantum effects at low temperature. iii. The protons in CH4 and the deuterons in CD4 carry a nuclear spin resp. Ip = 1/2 and I. = 1, which gives rise to spin-isomerism. Thus, CH4 has three spin varieties, meta (A1, In = 2), ortho (T2, in = 1) and para (E, In = 0). The isomerism may be expected to have profound influence on the phase diagram of solid methane.

scholarly journals Electric properties of olive oil under pressure

2021 ◽  
Author(s):  
L. T. Pawlicki ◽  
R. M. Siegoczyński ◽  
S. Ptasznik ◽  
K. Marszałek
Keyword(s):  
Molecular Structure ◽  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Olive Oil ◽  
Material Parameters ◽  
First Order ◽  
Long Time ◽  
Capacitive Reactance ◽  
First Order Phase

AbstractThe main purpose of the experiment was a thermodynamic research with use of the electric methods chosen. The substance examined was olive oil. The paper presents the resistance, capacitive reactance, relative permittivity and resistivity of olive. Compression was applied with two mean velocities up to 450 MPa. The results were shown as functions of pressure and time and depicted on the impedance phase diagram. The three first order phase transitions have been detected. All the changes in material parameters were observed during phase transitions. The material parameters measured turned out to be the much more sensitive long-time phase transition factors than temperature. The values of material parameters and their dependence on pressure and time were compared with the molecular structure, arrangement of molecules and interactions between them. Knowledge about olive oil parameters change with pressure and its phase transitions is very important for olive oil production and conservation.

scholarly journals SUPERCONDUCTING PHASE TRANSITION IN THE NAMBU–JONA-LASINIO MODEL

2001 ◽  
Vol 16 (17) ◽  
pp. 1129-1138 ◽  
Author(s):  
M. SADZIKOWSKI
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Superconducting Phase ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Rich Phase ◽  
Quark Interaction ◽  
Quark Coupling ◽  
Superconducting Phase Transition

The Nambu–Bogoliubov–de Gennes method is applied to the problem of superconducting QCD. The effective quark–quark interaction is described within the framework of the Nambu–Jona-Lasinio model. The details of the phase diagram are given as a function of the strength of the quark–quark coupling constant G′. It is found that there is no superconducting phase transition when one uses the relation between the coupling constants G′ and G of the Nambu–Jona-Lasinio model which follows from the Fierz transformation. However, for other values of G′ one can find a rich phase structure containing both the chiral and the superconducting phase transitions.

QUANTUM PHASE TRANSITIONS AND ENTANGLEMENT IN J1–J2 MODEL

2004 ◽  
Vol 15 (08) ◽  
pp. 1095-1103 ◽  
Author(s):  
RECEP ERYIĞIT ◽  
RESUL ERYIĞIT ◽  
YIĞIT GÜNDÜÇ
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Ground State ◽  
Abrupt Change ◽  
Quantum Phase Transitions ◽  
Nearest Neighbors ◽  
Competing Interactions ◽  
One Dimensional ◽  
Transition Points

We study ground state pairwise entanglement within one-dimensional spin-1/2 antiferromagnetic J1–J2 model with competing interactions. Contrary to some claims we found that frustration does not increase entanglement. Concurrence of nearest and next nearest neighbors are found to show abrupt change at phase transition points. We also show that the concurrence can be used to classify the phase diagram of the model in anisotropy–frustration plane.

THE GROUNDSTATES AND PHASES OF THE TWO-DIMENSIONAL FULLY FRUSTRATED XY MODEL

2009 ◽  
Vol 23 (20n21) ◽  
pp. 3939-3950
Author(s):  
PETTER MINNHAGEN ◽  
SEBASTIAN BERNHARDSSON ◽  
BEOM JUN KIM
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Xy Model ◽  
Two Dimensional ◽  
Spin Configuration ◽  
Multicritical Points ◽  
Symmetry Phase

The 2D Fully Frustrated XY(FFXY) class of models is shown to contain a new groundstate in addition to the checkerboard groundstate of the standard 2D XY model. The spin configuration of this additional groundstate is obtained and its connection to a broken Z2-symmetry explained. This means that the class of 2D FFXY models belongs within a U(1) ⊗ Z2 ⊗ Z2-symmetry phase-transition representation. The phase diagram is reviewed and the central charges of the four multicritical points described. The implications for the standard 2D FFXY-model are discussed and elucidated, in particular with respect to the long standing controversy concerning the phase transitions of the standard 2D FFXY-model.

scholarly journals Фазовая диаграмма и особенности поведения мягких мод в твердых растворах со структурой хантита TbFe-=SUB=-3-x-=/SUB=-Ga-=SUB=-x-=/SUB=-(BO_3)-=SUB=-4-=/SUB=-

2022 ◽  
Vol 130 (1) ◽  
pp. 84
Author(s):  
А.С. Крылов ◽  
А.Н. Втюрин ◽  
И.А. Гудим ◽  
И.В. Немцев ◽  
С.Н. Крылова
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Raman Spectra ◽  
Solid Solutions ◽  
Structural Phase ◽  
Temperature Phase ◽  
Structural Phase Transitions ◽  
Soft Modes ◽  
Temperature Phase Diagram

The Raman spectra of four crystals of TbFe3-хGax (BO3) 4 solid solutions (x from 0 to 0.54) were studied in the temperature range from 8 to 350 K. The temperatures of structural phase transitions were determined. The observed spectral behavior is characteristic to condensation and restoration of soft modes. Soft modes are associated with a structural phase transition from the R32 phase to the P3121 phase. The Compositions-Temperature phase diagram was constructed

Magnetic Properties of a Binary Mixture of Paramagnetic Metallomesogens

1997 ◽  
Vol 488 ◽  
Author(s):  
Y. Shimizu ◽  
S. Tantrawong ◽  
M. Yoshida ◽  
T. Sugino
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Magnetic Properties ◽  
Phase Transitions ◽  
Binary Mixture ◽  
Binary Phase Diagram ◽  
Full Range ◽  
Antiferromagnetic Interaction ◽  
Ferromagnetic Behavior ◽  
Pure Compounds

AbstractMagnetic properties of a binary mixture of mesogenic tetraphenylporphyrin Cu(II) and VO(IV) complexes are reported. These mesogens show two lamellar mesophases (DL and DLC) and a binary phase diagram revealed that each mesophase is miscible. The magnetic properties were investigated by magnetization measurements using SQUID. It was found that the magnetization of 1:1 mixture (mole% base) was larger than those of the pure compounds below ca. 190 K, whilst 1:3 and 3:1 mixtures showed the decrease of magnetization in the full range of temperature in which the measurements were carried out. It was shown that χ−1 vs. T plots did not obey Curie-Weiss law. For the VO(IV) complex and 1:1 mixture, stepwise changes could be recognized at the temperatures corresponding to the phase transitions. 1:1 mixture as well as Cu(II) and VO(IV) complexes totally involve antiferromagnetic interaction. However, ferromagnetic behavior in χ−1 vs. T plots was seen about DL - DLC phase transition.

Magnetic Field-Induced Phase Transitions in Ferrofluid Emulsion

1996 ◽  
Vol 10 (23n24) ◽  
pp. 2973-2981 ◽  
Author(s):  
Yun Zhu ◽  
M.L. Ivey ◽  
P. Sheaffer ◽  
J. Pousset ◽  
Jing Liu
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Volume Fraction ◽  
Emulsion System ◽  
Liquid Crystal Phase ◽  
Critical Fields

Two field-induced phase transition regimes are found in a ferrofluid emulsion system, which are defined by three critical fields, Hc1<HC2<Hc3. The first regime, which starts at Hc1 and finishes at Hc2, is the transition from a gas to induced Nematic liquid crystal phase. In the second regime, or Hc2<H<Hc3, induced Nematic liquid crystal transits to columnar solid structure. A phase diagram is drawn and is explained well by a scaling calculation, which gives Hc1~Φ−1/2, Hc2~Φ−1/4, and Hc3~Φγ exp (πG/Φγ/2), where Φ is the volume fraction, γ=0.172 and G=1.44.

scholarly journals Uniform quenching processes in a holographic s + p model with reentrance

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
Chuan-Yin Xia ◽  
Zhang-Yu Nie ◽  
Hua-Bi Zeng ◽  
Yu Zhang
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Time Evolution ◽  
Normal Phase ◽  
Holographic Model

AbstractWe study the homogenous quenching processes in a holographic s + p model with reentrant phase transitions. We first realize the reentrant phase transition in the holographic model in probe limit and draw the phase diagram. Next, we compare the time evolution of the two condensates in two groups of numerical quenching experiments across the reentrant region, with different quenching speed as well as different width of the reentrant region, respectively. We also study the dynamical competition between the two orders in quenching processes from the normal phase to the superconductor phase.

scholarly journals ORBITAL SELECTIVE PHASE TRANSITION

2013 ◽  
Vol 27 (20) ◽  
pp. 1330015 ◽  
Author(s):  
YAO YAO ◽  
YU-ZHONG ZHANG ◽  
HUNPYO LEE ◽  
HARALD O. JESCHKE ◽  
ROSER VALENTÍ ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Hubbard Model ◽  
Crystal Field ◽  
Crystal Field Splitting ◽  
Coulomb Interactions ◽  
Itinerant Electrons ◽  
Theoretical Investigations ◽  
Spatial Fluctuations

In this paper, we review theoretical investigations on the origin of the orbital selective phase where localized and itinerant electrons coexist in the d shell at intermediate strength of the on-site Coulomb interactions between electrons. In particular, the effect of spatial fluctuations on the phase diagram of the two-orbital Hubbard model with unequal bandwidths is discussed. And different band dispersions in different orbitals as well as different magnetically ordered states in different orbitals which are responsible for orbital selective phase transitions are emphasized. This is due to the fact that these two mechanisms are independent of the Hund's rule coupling, and are completely distinct from other well-known mechanisms like orbitals of unequal bandwidths and orbitals with different degeneracies. Moreover, crystal field splitting is not required in these two recently proposed mechanisms.

scholarly journals Detecting scaling in phase transitions on the truncated Heisenberg algebra

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Dragan Prekrat ◽  
Kristina Neli Todorović-Vasović ◽  
Dragana Ranković
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Heisenberg Algebra ◽  
Infinite Matrix ◽  
Transition Line ◽  
Matrix Size ◽  
Phase Transition Line ◽  
Size Limit

Abstract We construct and analyze a phase diagram of a self-interacting matrix field coupled to curvature of the non-commutative truncated Heisenberg space. The model reduces to the renormalizable Grosse-Wulkenhaar model in an infinite matrix size limit and exhibits a purely non-commutative non-uniformly ordered phase. Particular attention is given to scaling of model’s parameters. We additionally provide the infinite matrix size limit for the disordered to ordered phase transition line.

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