Quantcast
  • Register
PhysicsOverflow is a next-generation academic platform for physicists and astronomers, including a community peer review system and a postgraduate-level discussion forum analogous to MathOverflow.

Welcome to PhysicsOverflow! PhysicsOverflow is an open platform for community peer review and graduate-level Physics discussion.

Please help promote PhysicsOverflow ads elsewhere if you like it.

News

New printer friendly PO pages!

Migration to Bielefeld University was successful!

Please vote for this year's PhysicsOverflow ads!

Please do help out in categorising submissions. Submit a paper to PhysicsOverflow!

... see more

Tools for paper authors

Submit paper
Claim Paper Authorship

Tools for SE users

Search User
Reclaim SE Account
Request Account Merger
Nativise imported posts
Claim post (deleted users)
Import SE post

Users whose questions have been imported from Physics Stack Exchange, Theoretical Physics Stack Exchange, or any other Stack Exchange site are kindly requested to reclaim their account and not to register as a new user.

Public \(\beta\) tools

Report a bug with a feature
Request a new functionality
404 page design
Send feedback

Attributions

(propose a free ad)

Site Statistics

186 submissions , 146 unreviewed
4,738 questions , 1,939 unanswered
5,273 answers , 22,453 comments
1,470 users with positive rep
748 active unimported users
More ...

  Can isotropic to nematic phase transition in liquid crystals be made second-order?

+ 1 like - 0 dislike
2596 views

One normally says that the isotropic to nematic transition in liquid crystals has as order parameter a symmetric traceless tensor of rank-3. The cubic invariant is allowed by symmetries and, in agreement with the Landau theory of phase transitions, the transition is observed to be first-order. I was wondering if by tuning pressure or other parameters (mixture concentrantions) one can make the cubic term zero. This would be the case describe by Landau in 1937, which is the point O in the attached phase diagram - a critical point sitting on the line of first order transitions [Figure from the original paper by Landau]. I tried to look at the liquid crystal literature but I haven’t found any example of this. Maybe there is a simple microscopic reason why the cubic term cannot be zero? 

NB I am NOT interested in phase transitions in liquid crystals coupled to an external field controlling the direction of rods. I am only interested in a totally rotationally symmetric situation when the transition is reached by changing temperature, pressure, or other rotationally invariant parameter, such as the concentration.

asked May 18 in Theoretical Physics by Slava Rychkov (5 points) [ no revision ]

Your answer

Please use answers only to (at least partly) answer questions. To comment, discuss, or ask for clarification, leave a comment instead.
To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL.
Please consult the FAQ for as to how to format your post.
This is the answer box; if you want to write a comment instead, please use the 'add comment' button.
Live preview (may slow down editor)   Preview
Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:
p$\hbar$y$\varnothing$icsOverflow
Then drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds).
To avoid this verification in future, please log in or register.




user contributions licensed under cc by-sa 3.0 with attribution required

Your rights
...