Blog

Mon, 03/29/2021

The essence of Haldane phase is its energy gap. It is known that anti-ferromagnetic spin-1/2 chain has quasi long rang order and is gapless. This leads people to think that integer spin chain, with weaker quantum fluctuations, should also have quasi long rang order and should be gapless. Haldane...

Tue, 01/26/2021

In many cases, an anomaly corresponds to a SPT order or a topological order in one higher dimension.[1][2] This kind of anomalies are labelled by a discrete index. However, for continuous symmetries, Ref...

Wed, 10/28/2020

A dopon theory is an all-fermion slave-particle mean field theory for Cu high Tc superconductors, which was developed by Ribeiro and...

Sat, 10/03/2020

What is quantum spin Hall effect? According to Bernevig-Zhang and Kane-Mele, quantum spin Hall effect refers to quantized transverse Sz-spin current induced by force acting on...

Mon, 09/21/2020

The particles in our world can be divided into two classes: those with Bose statistics (such as photons, Hydrogen atom, etc) and those with Fermi statistics (such as electron, quark, etc). The possibility of third kind of particles with fractional statistics in 2-dimensional space was pointed...

Sat, 09/12/2020

In 2013, I wrote a paper (arXiv:1305.1045) claiming solved the chiral fermion problem. It is known that some gauge-anomalous chiral fermion theory cannot be put on a lattice in the same dimension. However, for a long...

Wed, 09/09/2020

For a long time, people thought Landau symmetry breaking theory can describe all phase transitions and all phases of matter. When encounter a new phase of matter, people first first try to identify the symmetry breaking...

Mon, 09/07/2020

Peolpe have been working on J1-J2 model for 30 years. Here is a recent tensor network calculation. Comparing with the following meanfield result may give us some hint on what is the discovered gapless spin liquid state near J1=J2.

 

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Sat, 09/05/2020

The following picture

has mountain, lake, trees, snow,... ..., and light.

If we look closer, we see
...