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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Phase of refrigerant when entering evaporator?

In the diagrams for refrigeration cycle(vapour-compression), the refrigerant at the inlet to the evaporator lies under the vapour dome i.e partly vapour and partly liquid. Now i have been studying ...
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Classical statistical model based on group multiplication

For a (finite) group $G$, consider the following classical statistical model on a 2 dimensional lattice with oriented edges: Each edge carries a classical degree of freedom that can take values in ...
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Is there an intuitive reason as to why there is no phase transition to get to a degenerate Fermi gas?

Cooling a bosonic gas leads to a phase transition into the Bose-Einstein condesate. This is characterised by a symmetry broken ( U(1), by choosing a specific phase for the macroscopic wavefunction) ...
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Phase transition and energy conservation inside neutron star

I'm stuck at the moment with this simple question: If a phase transition from hadronic to quark matter of 1st order with a big jump in the energy density occurs inside a neutron star one can get ...
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178 views

Data for plotting phase changes in water

I want to plot phase diagrams of water that show its density, heat capacity, and entropy as it undergoes various first order (discontinuous) phase transitions with increasing temperature. I'm ...
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What would happen to a 10 meter sphere of room temperature water if released into space?

Imagine that we had a space station with a relatively large hangar, and we allowed a ball of water to accumulate that had a 10 meter diameter and a water temperature of 20C. While the hangar is ...
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Why does a vanishing energy gap indicate a phase transition?

More concretely: When looking at the Ising model in the description of Bogoliubov fermions, we get an explicit expression for the energy gap, that vanishes for a particular value of the magnetic field....
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Why does $[H,N]=0$ violate with superfluid phase judgement $\left<b\right>=0?$

I'm working with the standard Boson Hubbard model. It's Hamiltonian is defined in Fock space and commutes with total particle number N. $$[{{\hat H}_{BH}},\hat N] = 0$$ So I can simultaneously ...
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Does carbon form a gas in the absense of oxygen?

If I take pure carbon and heat it in an inert atmospher, at what temperature will it vaporize into carbon gas?
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As the universe expands, do we have any reason to suspect further separation of the fundamental forces/interactions?

At some point, all four forces were one force. (another question: what exactly does that mean?). At some point gravity and the strong force separated out leaving the electroweak force. Then the ...
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Apparition of scale invariance

When did "scale invariance" started to be seen as an important concept in the theory of phase transition? Phase transition and critical points started to be investigated in earnest in the middle of ...
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Symmetry breaking - mixed state in $T\rightarrow 0$ limit

In the quantum$^1$ system with a continuous symmetry (in the Thermodynamic limit) relating the ground states $\newcommand{\ket}[1]{\left|#1\right>}\{\ket{\theta}\} \newcommand{\bra}[1]{\left<#1\...
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Correlation length at low temperatures?

The correlation length gives (approximately) the distance over which a spin flip has an effect. For systems with ordered phases, at low temperatures the correlation length is then small (since a ...
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Why is the latent heat of fusion of helium-3 a negative quantity?

I am new to this community and I have little to no background in physics, so I apologise should I make a glaring factual mistake in my question. I briefly studied the phase transitions of matter and,...
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Difference in calculation of Ginzburg Criterion in Gaussian and Mean-Field theory?

In the past I asked this question asking about a subtlety in the Ginzburg criterion for mean field theory and the Gaussian approximation. I am now having a hard time determining in general what is ...
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Percolation in Bethe Lattice with Alternating Neighboor Numbers

Suppose we have a Bethe Lattice with alternating numbers of neighbours,starting from 3 and then 4 and so on. So the zeroth point has 3 neighbours, each of those 3 first neighbours has 4 neighbours (3 ...
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Phase Transitions (Statistical Mechanics) Book Recommendation

I am Studying Phase Transitions, starting from simple VdW equation up to Mean-Field&Landau Theory. I have many books such as Huang Kerson-Statistical mechanics, Yeomans- Statistical Mechanics of ...
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Why should the vapor pressure exist at all tempratures?

According to P-T phase diagram, at a constant pressure, liquid and gas attain equilibrium only at a certain temperature, (i.e. boiling point). So in a situation where I'm keeping a liquid in a closed ...
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Do solids do something analogous to liquids evaporating below their boiling point?

I'm probably not entirely right, but evaporation differs from boiling in that it is surface rather than bulk phenomenon driven by a pressure gradient rather than temperature. If a volume of liquid is ...
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How does Landau theory describe first order phase transitions?

We know first order phase transitions, like second order transitions, also have order parameters. They too can be dealt with Landau theory. What kind of temperature dependence of the order parameter ...
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What is the difference between vapor and liquid with same temperature?

When the temperature is same, it means that the kinetic energy of the particles of both phases are the same, so what is the difference between a vapor and liquid of a substance, such as ethanol, when ...
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Is there a material that boils when heat is removed at constant pressure?

Echoing the marvelous question of a material that freezes when heat is added at constant pressure, I am wondering whether there is a material that would boil when heat is removed at constant pressure. ...
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Can steam freeze via adiabatic expansion?

Context: At the end of animation movie Steamboy, a huge steam engine's pressure vessel breaks, which results in the escaped steam freezing to ice. I've been thinking about this -- is it really ...
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What can happen on the “other side” of Berezinskii–Kosterlitz–Thouless (BKT) transition?

There is a generalized concept of Berezinskii–Kosterlitz–Thouless (BKT) transition in any dimension [not just in 2 dimensional classical system or 1+1 dimensional quantum system], such that the ...
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Why do really cold objects evaporate really quick? [closed]

So I saw a video of LNG (liquid natural gas) and when it got in contact with water, which was room temp the LNG evaporated instantly...why? Ice takes a while to evaporate like a sec even when hot ...
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Can you make a metal denser by melting it and make it cool down under high pressure?

The answer is probably no. But can you make a metal denser by melting it and make it cool down under high pressure? Or would it just crack under internal stress when it returns to a solid? I'm going ...
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Can I change solid into liquid, gas or solute by cutting again and again until it is a molecule particle?

If I have small piece of solid, for example, pure iron powder, fine sand , (at room temperature) then I cut it slowly into half again and again. Every times, after I cut it, I wait for temperature ...
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Energy conservation in cosmological phase transitions

Let us consider a cosmic phase transition, in which fermions $\psi_f$ condense and the vacuum expectation value $|\langle \bar{\psi}_f \psi_f\rangle |$ of the resulting fermion-bilinear field gives ...
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What is the difference between the states of matter and the phases of matter?

What is the difference between the states of matter and the phases of matter? Should solid, liquid and gases be called states of matter or phases? How many states and phases are there? Different ...
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What's the meaning of QCD phase transition temperature?

I read about the QCD energy level in various sources, eg: Wikipedia, and this gives a phase transition temperature of about 200 MeV, above which quark confinement breaks down and we may observe ...
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Why is Wilson's work so relevant in particle physics? I thought that critical phenomena were described by CFTs

If I have understood the subject correctly, Wilson correctly explained the second order phase transitions and was able to compute the critical exponents of several of them using the Renormalization ...
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Understanding entanglement entropy in the transverse field Ising model

I'm working on a project studying the transverse field Ising model in 1D with periodic boundary conditions, given by $$H = - J \sum_{i=1}^{N} \sigma^z_i \sigma^z_{i+1} - h \sum_{i=1}^N \sigma^x_i$$ I ...
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Ginzburg-Landau theory for first-order phase transitions?

In AlQuemist's answer to this PSE question:223892 and Thomas' recent answer to one of my questions. There is a mention of the application of the Ginzburg criterion and in general the Ginzburg-Landau ...
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Ginzburg Criterion - why average over the Correlation Length?

To derive the Ginzburg criterion for the upper-critical dimension the fluctuations are averaged over a volume set by the correlation length. Why is this done? i.e. why do we average over a volume in ...
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Are order parameters ultimately subjective?

I keep bumping into order parameters in scientific papers, reviews, articles, etc, but I can never get a firm grip on them. Order parameters seem terribly subjective to me. Basically the way I ...
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Can water boil at 100% absolute humidity?

The definition of absolute humidity is the amount of water that can exist in solution with air as a gas. My question is, in a closed vessel that contains a flask and a burner or heat source below it ...
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Does a gap closing mean an occurrence of a quantum phase transition?

If we have observed a closing of the excitation gap in the energy spectrum of a certain model, can we safely conclude that a quantum phase transition occurs?
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Why is the melting point of water independent of pressure?

I've read here that the boiling point of water is highly dependent on the pressure, whereas the melting point is independent of the pressure. Why is that? Is that true in general?
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Why is a collection of non-interacting bosons pathological?

In this lecture titled "Disorder and Interactions: From Spin Chains to Cold Atoms" the speaker Thierry Giamarchi claims that a collection of non-interacting bosons is totally pathological. His argues ...
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Interpretation of Ising model simulations

I've been working on numerically solving the Ising model in a study of phase transitions, but I'm having difficulty finding material to help me discuss the results. I'm studying spontaneous ...
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Insulator behavior of large U limit in Hubbard model

I am now learning the many-body physics and having some questions about the insulator behavior of large $U$ limit for the Hubbard model : \begin{equation} H = -t\sum_{\left\langle {i,j} \right\rangle,...
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Feynman Lectures Vol I 41-4: Find the number of collisions received by a water molecule per second

In The Feynman Lectures on Physics Vol. I Ch. 41: The Brownian Movement, $\S4$ The random walk we are told: The reader may easily verify that the number of collisions a single molecule of water ...
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Unphysical region of Helmholtz free energy for Van der Waals gas

Recently, while looking at the Van der Waals gas and its implications for phase transitions I stumbled across a problem. We derived the normal Van der Waals gas equation: $$ \left(p+\frac{aN^2}{V^2}\...
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Does (spontaneous) symmetry breaking imply long-range order and vice-versa?

Crystalline solids have a long-range order (where symmetry is broken) but liquids have only a short-range order (where no symmetry is broken). Ferromagnets have a long-range magnetic order while a ...
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Is a transition from multidomain to single domain a phasetransition?

Is the transition from a multodomain state to a single domain state a phase transition? E.g. in a ferromagnet as a function of field from a multidomain state at low fields to a single domain state at ...
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What happens when you put water under intense pressure?

Pretend you have an indestructible tube that cannot leak, inside which is water. Imagine that in each side of the tube, you have very powerful pistons What would happen if you compress the water ...
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Is the Landau free energy scale-invariant at the critical point?

My question is different but based on the same quote from Wikipedia as here. According to Wikipedia, In statistical mechanics, scale invariance is a feature of phase transitions. The key ...
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How to get the phase transition diagram for a coexistence phase simulation?

I am running a lammps program to get the phase transition diagram. one for gold and the other for silicon. I am measuring the melting point by investigating the growth of each phase at different ...
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Space tranlsation symmetry breaking

If the given wave function of many particle system which is in liquid phase (say) is ,$$\psi( \vec{r_{1}},\vec{r_{2}},\vec{r_{3}},....\vec{r_{n}})$$ Probability density of finding the single particle ...
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Differentiating Landau free energy functional from the energy levels of a system

I quote from Huang's Introduction to Statistical Mechanics (not the book Statistical Mechanics), page 266 Consider, for simplicity, a one-component order parameter, a scalar field $\phi(x)$ over a ...