# Tag Info

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Within the standard model: It cannot! Even though there is CP violation in the SM (as you state), the amount is not enough to give the ratio of $\frac{n_B}{n_\gamma} \sim 10^{-10} \ .$ Furthermore, the electroweak phase transition (EWPT) in the SM is not even a second order transition, but merely a crossover. In order to render the transition ...

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The first thing to realize is that there are no "true" phase transitions (in the sense of non-analytic behaviour of thermodynamic potentials) in finite systems. This is the main difficulty one faces when analysing phase transitions using (most) computer simulation schemes. In particular, such simulations are only reliable as long as the observed correlation ...

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At the critical point, we have $\Psi(\vec r) = 0$ because that's the basic way in which this whole Landau theory works. First of all, it's important to realize that while making such statements, we consider the case of zero external field, so the term $Bh(\vec r) \Psi(\vec r)$ drops. Without this term, considering the constant configurations (in space) ...

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At research laboratories where liquid nitrogen (and oxygen) are commonly used every day, closed containers of LN and LOx are routinely transferred and stored. These pressurized tanks typically operate at around 20 atmospheres and hold between 50 and 250 liters. For short-term needs and operations, the LN will be transferred to a vented vacuum-jacketed ...

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I looked up the vapour pressuer of carbon dioxide at room temp (20 deg. C) and it is 57 bar, so I don't think you can have seen a cylinder of CO2 at 250 bar. If it is advertised as containing '250 bar' then the reality will be a lower pressure plus some solid CO2 in the bottle as well. For nitrogen, commercial cylinders can be supplied up to about 200 or ...

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Polymers such as wax definitely undergo phase transitions. You inquired about paraffin wax, which is oil-based. Paraffin wax is made of long rod-like molecules called linear straight-chain alkanes. It's solid at room temperature, but when refined as liquid paraffin and combined with water, it can act as liquid crystal, which complicates its phase diagram. ...

0

Ice has a sharp melting point temperature because it is a pure substance. Wax is a mixture of higher molecular weight hydrocarbons, so it doesn't have the same sharp melting point. While I have petrochemical experience in my background, I didn't work much with waxes, so I can't give you a firm estimate of the composition, but I suspect that web searches ...

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This comes down to the fact that ice is a crystal, and wax (and chocolate) is a (glassy) polymer-like material. Here is the chart of stiffness of a polymer as it is heated. When it is cold, the polymer is in a glassy phase. As it is heated, it enters the "leathery phase", and it begins to soften. As it warms up more, the material becomes progressively ...

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The transition between the two phases is called (not unreasonably!) a phase transition, and phase transitions come in two flavours: first order and second order. First order phase transitions (generally) have a sharp transition temperature. Steam condensing to water is a first order phase transition and as you've pointed out occurs at 100ºC (at one ...

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Neutron degenerate matter can undergo a phase transition to a superfluid state. The process is thought to be analogous to Cooper-pairing, but the coupling interaction due to the long-range nuclear force is of order 1 MeV, so can occur at temperatures below about $10^{9}$ K in neutron star interiors. The neutrons (fermions) form bosonic pairs in an analogous ...

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At least in the context of ultracold atomic fermions, the answer is no. The creation of a degenerate fermi gas is, unlike a BEC, not a phase transition. One major caveat: if there is an attractive force between the fermions, one can get a BCS-like phase transition to condensation of paired fermions. This is, of course, the case for electrons in metals, as ...

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