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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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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165 views

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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449 views

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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224 views

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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162 views

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 ...
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124 views

Van der Waals gas and non physical regions

When we draw P-V diagram of a Van der Waals gas, we get loops and since in the centre region of the loops, $\frac{dP}{dV}$ is +ve. Based on these regions we argue that the gas is unstable in that ...
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Refrigerant vs water heatpipe [closed]

For a heatpipe that is connected to a 50 Celsius object on one side,and a heatsink at 23 Celsius air at other side, what fluid filling will give better heat conductivity? Plain water, or some kind of ...
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433 views

Pressure-temperature dependence of a pure substance

Saturation temperature is defined as the temperature at which a pure substance say water, changes phase, at a fixed pressure. So water boils at 100⁰C , if the external pressure is kept constant at 101....
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What factors affect the critical temperature of a material?

I recently started learning electricity in A level physics and came across the concept of superconductivity. I find this very intriguing due to its capabilities. My questions are: What are the ...
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How can frozen clothes dry overnight?

I put some wet Polyester clothes outside for the night (the clothes were washed by hand with pretty cold water -maybe around 4°C- and wringed by hand so there was still water dropping of them when I ...
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103 views

Is the $\lambda$ point in superfluid helium understood?

When liquid helium is cooled below a certain temperature, it undergoes a second phase transition from He I to He II. The specific heat spikes at the famous lambda point. Is this spike in the specific ...
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Strange ice found in my garden

This morning I found a really strange ice formation in my garden. I can't figure out how it appeared, because there was nothing above. The night was particularly cold (Belgium). To give an idea, it ...
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Why are symmetric quantum ground states cat states iff the ground-state manifold is degenerate?

The usual story of symmetry-breaking quantum phase transitions (I won't consider topological transitions here) goes like this: you have a Hamiltonian $H(g)$ describing an infinite system which depends ...
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What is the difference between vapour and steam?

What is the difference between vapour and steam? These two terms seemingly are similar but have different meanings. trying to define these two gets us a similar definition which is not actually true I ...
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Do hierarchical condensates yield instantaneous or sequential symmetry breaking?

I am wondering whether the formation of a hierarchical vacuum condensate yields an instantaneous or sequential symmetry breaking in a cosmological phase transition. Let me illustrate this question ...
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Meaning of the term “phase” in chemistry and thermodynamics

I have some doubts about the definition of the term “phase” in chemistry and thermodynamics (is the meaning the same?). The "textbook" definition is: "A phase is a form of matter that is uniform ...
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How realistic is it to dry clothes in freezing weather?

There are stories about clothes freezing and drying in cold weather. The typical reason given for that is that the water is undergoing sublimation (ice -> vapor). The phase diagram for water is In ...
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Phase Transition in Graphene, classical or quantum approach?

Graphene is a high quality 2D crystal, which is stable at room temperature is amazing because in the 1930's Landau and Peierls showed that thermodynamics prevented 2D crystals from existing in free ...
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92 views

Phase transition

Can transition from ferromagnetism exist in 1D chain of spins? I know that: $$\Delta F = 2J - kT\ln(N)$$ in the spin $1/2$ Ising model, where $N$ is the number of ways in which we can create the ...
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272 views

How to simulate a phase transition in Molecular Dynamics?

I am trying to simulate the phase transition for gold and silicon separately using LAMMPS. I got the melting point for gold right using the below code. ...
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Néel temperature versus Curie temperature in ferrimagnetic materials

I'm wondering whether ferrimagnetic materials have a Néel or Curie temperature (or both) and whether it depends on the material. They would be temperatures at which the material undergoes a magnetic ...
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Boiling point of barbecue sauce

Yes, I am serious. I thought it was interesting that I was reducing some fluid the other day, and I put in my alerting thermometer to warn me of a rising temperature which I expected as the water ...
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Ice cube in a thermally isolated system … Will any of it melt?

If an ice cube at $0$ °C is in a thermally isolated system on its own, will any of it melt? The chemistry teacher says it will reach a state of equilibrium of half ice and half water due to ...
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Order parameter of first-order phase transition in the Ising model

Let's consider the $d-$dimensional Ising model, with $d>1$. If we reverse the external magnetic field ($h \to -h$) at $T<T_c$ , there is a first-order phase transition where the magnetization $...
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Is it possible to explain evaporation using thermodynamics only?

I'm wondering whether it's possible to explain water evaporation using the theory of thermodynamics only, as opposed to the commonly cited statistical mechanics. Indeed, the usually given explanation ...
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How come metal isn't considered a state of matter?

I know in chemistry metals are a class of elements on the periodic table, but in physics metal is more like a state of matter. All of the elements that are called metals on the periodic table are ...