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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What's the equilibrium that results if a solid is placed in an empty container at constant temperature?

I'm confused at how to approach this question (in a chapter on phase transitions) since it is so general. My first instinct is to say that is depends on the materials P-T diagram and the temperature, ...
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Phase transition and effect on leptogenesis

What is the effect on leptogenesis in the standard model if the electroweak phase transition is (i) first order and (ii) second order?
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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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Phase equilibrium

For a 2 phase closed system: $$d(nG)=(nV)dP-(nS)dT+\Sigma\mu_idn_i$$ now the question is, when we can use formula, $$d(nG)=(nV)dP-(nS)dT,$$ for the above system, instead of the first formula, and why? ...
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Solution Cahn-Hilliard 1d for a domain of finite size

I'm trying to get the solution of the Cahn-Hilliard equation in 1d with a certain mass $C$. We have two components, and let's assume we have the relation $c_1+c_2=1$.Hence we take only the variable $c=...
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Phase Transitions and Bubble Nucleation

The potential for a first order phase transition is shown below The phase transition occurs from the spontaneous formation of bubbles. Inside the bubbles the field value is at the "true vacuum" and ...
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Is there an renormalisation for 2d ising yielding the accurate critical coupling, why?

2d-ising model is a classical model to which renormalisation may be applied to obtain information about criticality. The partition function has the form $$Z=\sum_{\sigma} e^{-H(\sigma,K)}$$ where $$...
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Is there a commonly accepted definition of a quantum phase definition for a finite lattice/set of particles?

As noted by Sachev, and in a previous question, https://www.physicsoverflow.org/41602/, there cannot be quantum phase transitions for finite systems (with bounded local Hilbert space dimension). The ...
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QM explanation why hot oil explodes when water pours on it [closed]

I have read this question: Why does hot oil explode when pouring water on it? It explains in a classical way clearly, that the boiling point of oil is hotter then water, and water changes to steam ...
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Why a superconductor expel magnetic lines of force from inside completely when cooled below critical temperature?

Suppose a superconductor which is in a normal state (i.e. $T>Tc$) is subjected to a magnetic field. As soon as magnetic field switched from 0 to some value, eddy currents will develop on the ...
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Phase transitions and Helmholtz vs Gibbs Free Energy

Gibbs phase rule for Gibbs free energy says that phases during a phase transition must be in mechanical, chemical, and thermal equilibrium, e.g. $T_1=T_2$,$G_1=G_2$, and $P_1=P_2$, where the ...
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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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Is water the only substance freezing at 0°C?

When reviewing with my son his science homework (12 years old = ~7th grade, 5ème in France), he told me that "when the phase transition graph shows a plateau between phases then the substance is pure. ...
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Will a metastable solid convert to it's more stable form upon heating to the transition temperature of the more stable form?

Let's say a solid has a stable phase (A) that exists below some temperature, T, and A transitions to another stable phase B above that temperature. If you take a solid sample of B and rapidly quench ...
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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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phase transitions and hysteresis

Some phase transitions exhibit a jump, while others exhibits hysteresis. I have read that jumps correspond to the Maxwell construction while hysteretic transitions correspond to the "delay convention"...
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NVT simulation of the phase transition

Why it is assumed to be incorrect to simulate,say, liquid-solid transition at constant volume (NVT simulation)?
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Melting ice made with tap water

I recently froze some tap water in plastic bottles and I later made the ice melt completely (the idea was keeping ice bottles nearby me to fight the heat). When the water returned to liquid a lot of ...
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Shape of isotherms in $P$-$V$ phase diagram

Please explain the shape of the isotherms in this P-V phase diagram. In particular, why are the isotherms flat in the liquid-vapor region? (image from Lumen Learning | Physics | Phase Changes)
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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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Flow velocity ambiguity in transition region

I have calculated the following short table concerning the stationary flow of water in a 1 meter long pipe with a diameter of 16 mm and a completely smooth inner surface. The flow is driven by the ...
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A query on the equation $TdS = dU + PdV$ (relating to phase changes)

$TdS=dU+PdV$ is one of my favourite equations in all of physics. I have used it many times, in particular to obtain the Helmholtz free energy; my favourite state function. One thing I am not 100% ...
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Some ambiguous points on Spontaneous Symmetry Breaking (SSB)?

Almost in every textbook of condensed matter physics, the standard description of SSB could be formulated as follows: Consider the lattice Heisenberg model in an external magnetic field $H=\sum_{ij}...
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Is the Mpemba effect exclusive to water?

Is the Mpemba effect exclusive to water ? So I was reading this post about really cool phenomena where hot water freezes faster than cold water. But it only talks about water. Even online student ...
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Kosterlitz-Thouless transition and renormalisation group theory

I'm trying to understand the Kosterlitz-Thouless transition in 2d systems. There is a section in Altland and Simons' Condensed Matter Field Theory that discusses the phenomenon, but I don't really ...
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Non-ideal Gases under fixed external parameters

When discussing non-ideal gases, the first qualitative observation that is made is that specifying the internal parameters of a system does not uniquely determine an equilibrium state. The possible ...
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Different concepts of phase transitions in spin models

I am currently revising the lecture notes in which different spin systems are analyzed, focussing on the occurrence (or absence) of phase transitions. Different techniques are applied to analyze the ...
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Quantum ising/heisenberg model, states representation

I am working with a hamiltonian which looks like this (Heisenberg model) I have made a program which computes this hamiltonian using Pauli matrices (spin 1/2). My working space is then the tensor ...
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Why is boiling water loud, then quiet? [duplicate]

Water in my electric kettle makes the most noise sixty to ninety seconds before the water comes to a full boil. I have been fooled many times by the noisy kettle, only to discover that the water was ...
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How are drawing common tangents to get diffusion different for concave and convex phase fields?

Whenever there is a concept of diffusion involved and we need to decipher what is going to happen we tend to draw common tangent s in the phase field diagrams and decide which direction the diffusion ...
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Is energy minimization a valid consideration even in dynamic/evolution based problems like phase transitions?

As an example, binary mixture phase separation in liquid due to quenching is typically explained by saying that because of decrease in temperature, the free energy landscape is such that splitting up ...
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Why doesn't the phase diagram of water look different?

How can sublimation occur at much lower temperatures than 0 degrees celsius provided that the pressure is sufficiently low? The melting point of water is relatively unaffected by the external pressure ...
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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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Do any substances have the same density when solid and liquid?

I know that as you heat something it expands, but this is proportional to the change in temperature, so if I compare the density of a liquid right before freezing and right after then the thermal ...
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Thermal hysteresis and its physical significance in lipid membranes?

We usually associate the phenomenon of hysteresis with memory in the system. For example, magnetic hysteresis is the basis of hard disks(if I recall it correctly). There are also electronic circuits(...
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How do we cool gases to the $mK$ range?

When we set new records for coldest temperature in the universe, we usually do it with gases (see: https://physicsworld.com/a/millikelvin-cooling-of-large-molecules-is-no-myth/) How do we pull this ...
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Why does renormalizability mean that “ultimately locality will have to be abandoned”?

This is stated by Zinn-Justin in his paper Quantum Field Theory: renormalization and the renormalization group: Low energy physics does not depend on all the details of the microscopic model ...
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What are the necessary or sufficient conditions for a renormalization group scheme to be “valid”?

Suppose I have a super operator $G$ which acts on Hamiltonians to produce a new Hamiltonian that is related somehow. For the purposes of this question, suppose that these Hamiltonians are defined on ...
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How to get mean field critical exponents for this Hamiltonian?

$$ \mathcal{H} = -J \sum_{\langle ij\rangle} \sum_{\alpha=1}^N s_i{}^\alpha s_j{}^\alpha -g \sum_{\langle ij\rangle} \sum_{\alpha\beta} (s_i{}^\alpha s_j{}^\alpha) (s_i{}^\beta s_j{}^\beta) $$ Above ...
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Physical explanation of the characteristics of the order parameter of the transverse Ising Model

The Hamiltonian for transverse Ising model is $$\hat{H}=-\sum_{j=0}^{N-1}(\lambda \hat{\sigma}_j^x\hat{\sigma}_{j+1}^x+\hat{\sigma}_j^z)$$ where $\hat{\sigma}$s are Pauli matrices. This model shows ...
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Is a single radon-daughter atom in air, such as ${}^{218}\text{Po}$, a solid?

Is a single radon-daughter atom in air a solid? The Wikipedia article on radon says: Unlike the gaseous radon itself, radon daughters are solids and stick to surfaces, such as dust particles in ...
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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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Cooling effect caused by evaporation

Evaporation is said to cause cooling effect because it absorbs energy from surroundings to change its phase from that of a liquid to gas. I am in doubt as to why would the surroundings be ready to ...
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What is the critical temperature for a BKT transition in the 2D quantum XY model with $S=1$ (not $S=1/2$)?

What is the critical temperature for a BKT transition in the 2D quantum XY model with $S=1$ (not $S=1/2$)? For instance, the classical XY model has KTc/J = 0.898 and the quantum XY model with S=1/2 ...
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Ferromagnet $\leftrightarrow$ paramagnet at Curie temperature

I think it's like this: $\, m=\tanh\left(\frac{Bμ}{k_bT}\right)$. If now the temperature decreases, then $\mu$ increases, until it flattens out ($\tanh$ function). Is the a point where $m$ flats out, ...
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How can the Higgs field “sense” that the temperature is high enough to restore the broken symmetry above this temperature?

In the picture below of the potential of the Higgs field, we can see that the field has its highest energy if the field is zero, i.e. if no Higgs particles are present. The symmetry is restored at ...
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Phase transition in 2D Heisenberg model

When we study the two-dimensional isotropic Heisenberg Model using Mean Field Theory or by Monte Carlo simulation we observe a phase transition at a temperature not equal to zero. This is opposed to ...
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How do soft Pomerons become hard?

The exchange of soft Pomerons (and Reggeons) ($\alpha_R(0)=0.55$ and $\alpha_P(0)=1.08$) seem to describe total hadron-hadron cross sections pretty well in the Regge limit. See, for example: https://...
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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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Does superheated water have the same temperature as boiling water at room pressure?

According to David Tong’s notes on statistical physics on pages 139 to 140, a superheated liquid lies on an isotherm between the spinodial curve and the coexistence curve. Hence, does this mean that ...