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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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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216 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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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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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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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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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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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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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 ...
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Could a gas go directly to a solid without becoming a liquid?

If water vapor is pulled inwards and cooled at a fast enough rate could if be frozen back into a solid form? i understand that they would have to be froze together as soon as contact is made but if ...
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Why do solids cool when put in a vacuum chamber?

I was watching this video on YouTube where some snow was put in a vacuum chamber, and it cooled down a fair bit after depressurizing. Why is this? I understand that a gas would cool down because it ...
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When can water be supercooled?

Qualitatively, I understand that water can be supercooled when: It is relatively pure. It is in a container that is relatively smooth of defects. The effect of both of these is to reduce nucleation ...
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Why does water stop boiling immediately after turning off the heat?

When I am heating water on a gas stove, it begins to boil after some time and bubbles of air can be seen escaping out. However, as soon as I increase the amount of heat in the stove, the rate of ...
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Ratio of the two phases during phases transition (liquid-gas) : is it a general behavior of first order?

In the liquid-gas phase transition, we have a mixture between the two phases during the phase transition: a part of the volume is pure liquid and another part is pure gas, but the two are separated. ...
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Why does it take time to melt ice when the loss of magnetization of a material at its Curie temperature is immediate?

Everything is in the title: Why does it take time to melt ice when the loss of magnetization of a material at its Curie temperature is immediate? Have you an explanation for this difference?
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In an isothermal process how is the heat change non zero?

The temperature change in an isothermal process is zero. As a result (if the system is made of an ideal gas) the change in internal energy must also be zero. I don't want to consult the equations. I'm ...
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Universality classes in phase transitions : how is it precisely defined?

I would like to understand how we can say that two physical systems are in the same universality class. What I understand from this notion is that two systems are in the same universality class if ...
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261 views

Calculate the enthalpy of a pure compound with a cubic equation of state

I would like to calculate the enthalpy of a pure compound with a cubic equation of state (the ones deriving from the Van der Waals equation of state). I have an analytic expression of the heat ...
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Gas liquid phase transition : order parameter

I have found that the order parameter for a gas liquid phase transition is the difference of density : $\Delta \rho=\rho_g-\rho_l$. But I don't understand this definition. Indeed, an order parameter ...
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Form of Coulomb’s law before the electroweak phase transition

I’ve been thinking about the electroweak phase transition in the early universe, and I have some questions about the form of Coulomb’s law during that epoch. As I understand it, before the ...
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Van Der Waals model for liquid gas phase transition : Understanding Maxwell construction

I have a question on the context of Maxwell construction, spinodal lines. In this pdf https://www.uam.es/personal_pdi/ciencias/evelasco/master/tema_III.pdf they first compute the Van der waals model ...
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Phase diagram. When will I have a phase transition?

Take this phase diagram : At the point "A" I will have a liquid, at point B a gas. But what I want to know is : which phase do I have at point C. I know that this is precisely where the phase ...
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Stability, unstability (and metastability) in liquid gas phase transition : unstable in regards to what?

I have a question about the stability, unstability (and extra questin about metastability, between the spinodal lines if you have time), when we are having a liquid gas phase transition. Here, a ...
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Equilibrium between two thermodynamic phases : equality of gibbs potentials

I work in $(T,P,N)$ ensemble. I am studying a phase transition between a liquid and gas phase for the Van Der Waals model. In the pdf I am reading they say that when the two phases are at ...
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Liquid gas phase transition : question on convexity of free/gibbs energy and maxwell construction

I am trying to understand the liq-gas transition with van der waals model. And I am very confused by everything. Here is what I understood and I hope you will correct me. I consider the Free energy $...
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How can the Quantum Hall Effect consist of Topological Phase Transitions when there is no changing Topological Invariant?

I have read this article about Topology in Physics and had some problems understanding the Topological Phase Transition of the Quantum Hall Effect. The way I understood Topological Phase Transition, ...
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How does crystallization begin in a sodium acetate heat pack?

I have a pocket warmer heat pack, which is basically a plastic pouch containing a solution of sodium acetate and a flexible metal disk. When the solution is melted and super-cooled it doesn't ...
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Why does molten sand cool to form glass and not return to it's original yellow form?

I came across this website on the internet: http://www.explainthatstuff.com/glass.html. In this website, it is said that When molten sand cools, it doesn't turn back into the gritty yellow stuff ...