Questions tagged [phase-transition]

A phase transition is a change in the nature of a phase or in the number of phases of a system as a result of a change in the external conditions. Examples: melting/freezing, vaporization/condensation, ferromagnetic transition, superconducting transition.

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How does a capillary pressure drop affect evaporation?

Normally phase changes are said to occur at a constant pressure, but in situations with a capillary pressure drop (like a heat pipe as shown in the picture below) there is a difference in pressure ...
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Proof of Mermin-Wagner Theorem

There are many presentations of the proof of the Mermin-Wagner theorem in many different contexts (which talk about quantum vs. classical, existence of unique Gibbs measure or non-zero mean ...
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Melting point vs pressure

In my physics-class, I was told that, "The melting point of the same substance changes under different pressure. But it can change in two different manner" There are 2 different ways it can ...
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What is the relation between non-local order parameters and topological phases?

I know of several definitions of phases of matter: The first is the "old" one, Landau theory and symmetry breaking. In this definition we pick a local order parameter $m$ (as far as I can ...
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105 views

Renormalization group: Why is the correlation length only given by 'slow' modes

I am trying to understand the renormalization group approach to phase transitions. A central quantity is the correlation length $\xi$ given by $G(r) = \langle\phi(r)\phi(0)\rangle \sim e^{-r/\xi}$ for ...
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Physical meaning of gapped path between Hamiltonians in the same phase

I'm reading this famous paper about the classification of quantum phases, and I'm wondering about the physical meaning of the definition of phases the authors use. They say that two Hamiltonians $H_0$ ...
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When a gas condenses, how do you quantify the amount of the gas which turns to liquid? [closed]

I'm going through a question in Finn's thermal physics, I can't figure out part (c). I understand there will be some pressure change which will cause a certain portion of the gas to condense to ...
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What does liquid-vapor coexistence look like microscopically?

Suppose I have a prepared a fluid at conditions where liquid and vapor coexist at a common temperature. What does the interface between the two phases look like microscopically? If I scan an imaginary ...
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Could evaporation of a liquid into a gas be thought of as dissolving the liquid in a gas?

As I understand it, evaporation is thought of as a phase transition from a liquid into a gas. Individual molecules get enough energy to break surface tension, and flung up into the gas. A gas that's ...
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Why doesn't the state of matter oscillates between solid , liquid and gaseous phase?

I was reading about the London dispersion forces and it is written that it arises due to an asymmetric distribution of charges in an atom at an instant which gives rise to a temporal dipole and this ...
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First-Order Phase Transition

When the density/volume abruptly changes (isobar/isothermal) while providing a sufficient latent heat to the system, is this variation related to a high compression/expansion as it is illustrated to ...
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Thermodynamics - do all particles in a system undergo a state transition at exactly the same time?

Basic question: Why does temperature remain constant during a state change? The general answer I find in most places is that during a state change, the energy supplied is used to change the ...
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When pouring something on ice to make it melt at a lower temperature, does the energy required to melt it change?

When pouring something on ice, like deicing salt or vinegar, to make it melt at a lower temperature, does the energy required to melt it change (in a significant way)? Edit: I am only interested in ...
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How much of a "magnetic B field" can be expelled or shielded by a spherical superconductor or mu-metal sphere?

In a standard average 4 inch square magnet, What is the value of the Magnetic B field vector at a specified moment in time for such a magnet? Of that number, what is the direction of this particular “...
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Melt ice faster?

I had a discussion with a friend who claimed that vinegar is useful when defrosting a freezer because it lowers water's melting/freezing point. I disagreed, because I believe that the freezing point ...
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Why does the Ising model at the critical point have scale invariance?

If my current understanding of phase transitions and the renormalization group (RG) method is true, RG is a kind of 'zooming out' process, since this procedure makes a block of neighboring spins and ...
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What happens physically in a second-order liquid-gas phase transition?

I know the difference between first and second order phase transition in terms of the discontinuity of the derivatives of free energy. I am curious to know what happens as the system is viewed. ...
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Confusion 1D Bose-Hubbard Model Field-Theory

The General Setting I have some confusion concerning the interpretation of the field-theory describing the Bose-Hubbard Modell especialy in the one dimensional case. The general framework of the ...
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Superfluid Stiffness Definition

I am currently reading S. Sachdevs Book on Quantum Phase Transitions focusing on the Bose-Hubbard Model (Chapter 9) and especially the Dilute-Boson Field Theory (Chapter 16). When describing the fluid ...
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Is liquified gas rate of vaporization dependent on the volume of the container?

I have a vessel 50% full of ammonia at outdoor temperature of 20F - 100F depending on time of year. This vessel will be evacuated with a compressor and the vapor will be discharged into an ammonia ...
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Do quasicrystals exhibit topological order?

According to the book Quantum Information meets Quantum Matter, ordered phases can either be described by a Landau free energy: symmetry-breaking ordered phases; or there are different ways in which ...
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Negative critical exponent $\alpha$ for Superfluid helium at lambda point

Due to the positive critical exponent of the transition in liquid helium I would expect there to be no peak at the transition $t=0$. Since the $t$ dependent part of the specific heat should go to 0 as ...
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Why are there clear-cut states of matter instead of a gradual transition from gas to solid?

Why are there clear-cut states of matter instead of a gradual transition from gas to solid (let's set plasma aside for the purpose of this question)? If the main difference between them is the ...
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880 views

Why water behaves strangely at 4 degree celsius?

The basic physics concept I hope almost every one might be aware of i.e "water tend to expand instead of freezing just below and above 4 degree celsius". My question is why exactly at 4 ...
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What precisely does competing order mean?

I often see the term "competing order" thrown around in papers. What precisely does this refer to? It seems that it has something to do phase transitions, but can anyone offer a precise ...
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Can every first order phase transition be tuned to a second order phase transition?

Is every first order phase transition related to a second order phase transition by the tuning of some coupling? In practice is the expectation that the this tuning can usually be done in the lab. (By ...
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373 views

How do bubbles rise in water?

As a concrete example, consider boiling water. As water boils, bubbles form which rise to the surface. I know that things rise because of the Archimedes principle, however as far as I understand it, ...
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100 views

Critical field-theory action of the quantum rotor model with long-range Interactions

I am currently reading papers on the field theoretical description of phase transitions of the quantum rotor model for systems with algebraically decaying long-range interactions $J_{ij}\propto\frac{1}...
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Why doesn't the Teflon coating in cookware melt? [closed]

Teflon's melting point is 327 degrees Celsius, whereas a regular gas stove easily reaches temperatures above this. So why doesn't the Teflon coating in cookware melt while cooking?
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Pomeranchuk Effect

Pomeranchuk effect poses a paradox of order by disorder phase-transition. The liquid Helium-3 is in a liquid form close to absolute temperature. For high enough pressure, as you increase the ...
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Atmospheric pressure vs. boiling point equation

What is the relationship between the pressure of water and its boiling point? I am aware that a substance boils as soon as its vapor pressure equals that of the surrounding air. I have researched ...
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Does a vanishing self-energy imply a Gaussian fixed point in a $\phi^4$ theory below the upper critical dimension?

Assuming a QFT description of a second-order phase transition. From the free theory, one obtains some critical exponents and one performs an $\epsilon$-expansion below the upper critical dimension. ...
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Why is freezing something "fast enough" be approximated as adiabatic?

I am reading Scott Shell's Thermodynamics and Statistical Mechanics, and I just saw this statement: If freezing happens fast enough, to a good approximation the process can be considered adiabatic. ...
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What are the prerequistes for system to exhibit Anderson Localisation(AL)?

The existence of a localized phase in a disordered system tells us that system starting in a given initial superposition of energy eigen states continues to remain in that state in long time limit. ...
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Kuramoto model: a question about synchronization and critical couplings

Conisder a Kuramoto model on a graph with adjacency matrix $A$, $$\dot{\phi}_i=\omega_i+\lambda\sum_jA_{ij}\sin(\phi_j-\phi_i)$$ Consider the following order parameter, $$r(t)=\frac{1}{N}\sum_je^{i\...
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Are broken symmetry states non-stationary?

In his famous paper, More is Different (link), Philip W. Anderson states that in the context of quantum mechanics : [...] the state of the system, if it is to be stationary, must always have the same ...
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Does the isothermal compressibility diverge at the lambda line in Helium-4?

Helium-4 has a normal-superfluid phase transition which corresponds to the lambda line in the P-T diagram. The heat capacity at constant pressure $C_p$ shows a discontinuity when the lambda line is ...
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86 views

Phase transition in parameter (and not temperature) for a classical system

Consider the $q$-state Potts model on $\mathbb{Z}^d$ for some integer $q$ - this also has an FK-representation for any real number $q$. For $d = 2$ the model is exactly solvable and has a critical ...
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What is the real reason for evaporative cooling?

I have read two different explanations for evaporative cooling. The first is from my physics textbook: "As heat is transferred to a liquid, the average kinetic energy of its molecules increases. ...
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116 views

Why is the sequence of limits $\lim\limits_{V\to\infty}\lim\limits_{B\to 0}m(B,V)$ when reversed does not give the same result?

For spontaneous magnetization $m$ in a sample of volume $V$, what do the limiting operations $$ \lim\limits_{V\to\infty}\lim\limits_{B\to 0}m(B,V)=0,\\ \lim\limits_{B\to 0}\lim\limits_{V\to\infty}m(B,...
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Can phase diagrams be obtained by Helmholtz energy minimization?

I know that in calculating phases of materials it is standard to choose a pressure $p$ and temperature $T$ of interest and then, keeping these two quantities fixed, find the mixture of phases that ...
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Energy in the Ising model for liquid-gas transition

I am teaching myself statistical mechanics using the lecture notes of Professor Leonard Susskind. I am confused about a statement 'reducing $h$ reduces the density' at page $555$. I know the statement ...
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131 views

First-order phase transitions as branch cuts

First, I apologize for the long preface to my question. The actual question is in bold below. In Kardar's Statistical Physics of Fields, on page 10, the author writes, "the free energy of the ...
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Ising model critical temperature from divergence of the high temperature series

Consider the Ising model on a d-dimensional hypercubic lattice with nearest-neighbor coupling $J=1$: $$H=-\sum_{\langle ij \rangle}\sigma_i\sigma_j$$ For small $\beta$ (corresponding to high ...
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What happens to weight when ice melts? [closed]

A block of ice is weighed in a container. Then, it is left out to melt. Would the weight of the water be greater, less than, or equal to the ice? I know that it has something to do with density and ...
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100 views

Why is pressure constant during a phase change of water in a piston with a constant weight weighing down on the water?

If I take a piston (such as the classic expanding gas piston) with a constant weight on the plate and liquid water beneath the plate. I understand by Pascal's principle that the pressure is constant (...
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205 views

While freezing ice from salt water, does the salt dissolve in the ice or is it separated out?

I know that salt decreases the freezing point of water. We have freezing point (in Celsius), $\mathrm{T_f=-K_f\cdot m}$ (molality of salt). But, is it true that all of the solution doesn't freeze at ...
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Can a finite simple symmetry group be spontaneously broken in stages, with multiple phase transitions?

Can a finite simple symmetry group $G$ be spontaneously broken in stages, with two or more phase transitions, each one leaving a successively smaller unbroken subgroup? By simple, I mean no normal ...
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121 views

Continuous Transition From gas to liquid

Consider the following figure: Let us suppose we were at some point in gaseous phase. Can we go from gaseous to liquid phase by moving about critical point continuously? Why isn’t any critical point ...
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Topology of Renormalization group trajectories

In The renormalization group by Matthew Schwartz the is very interesting picture of RG for dimension and dimensionless couplings: Topology of such diagrams is very different. But this pictures ...

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