New release: v0.6.1.

Search found 11 matches

by steven_tao
10 Jun 2020, 00:47
Forum: HowTos and FAQ for TeNPy
Topic: overlap of ground states at different parameters
Replies: 5
Views: 157

Re: overlap of ground states at different parameters

The wilson loop \prod_{\theta \in \{0, 2\pi\}} \langle \phi_{gs}(\theta) \mid \phi_{gs}(\theta+\delta \theta) \rangle should be gauge free, although \langle \phi_{gs}(\theta) \mid \phi_{gs}(\theta+\delta \theta) \rangle is gauge dependent. Therefore, this formula can be used to numerically evaluate ...
by steven_tao
09 Jun 2020, 23:45
Forum: HowTos and FAQ for TeNPy
Topic: overlap of ground states at different parameters
Replies: 5
Views: 157

Re: overlap of ground states at different parameters

Thanks, Dr. Johannes. Then can we use the iDMRG to calculate the many-body winding number or berry phase ? For example, by replacing the hopping t by t e^{i \theta} , then many-body berry phase in periodic boundary is \gamma = i \int_0^{2\pi} d\theta \langle \phi_{gs}(\theta) \mid \partial_\theta \p...
by steven_tao
09 Jun 2020, 11:29
Forum: HowTos and FAQ for TeNPy
Topic: overlap of ground states at different parameters
Replies: 5
Views: 157

overlap of ground states at different parameters

Dear TeNPy Community: I am asking how to calculate the overlap of two ground states at two different parameters? For example, for parameter J1, we run the DMRG as: E_1, psi_1 = eng.run() At a different parameter J2, we run the DMRG as: E_2, psi_2 = eng.run() Then how we can calculate their overlap o...
by steven_tao
08 Jun 2020, 23:00
Forum: HowTos and FAQ for TeNPy
Topic: Adding a site to a chain perpendicularly
Replies: 6
Views: 1184

Re: Adding a site to a chain perpendicularly

The module lattice.IrregularLattice cannot be used after I upgrade TeNPy to a new version via pip install --upgrade physics-tenpy. After running the following code, the error message reads: TypeError: __init__() got an unexpected keyword argument 'remove'. import matplotlib.pyplot as plt from tenpy....
by steven_tao
22 May 2020, 11:31
Forum: HowTos and FAQ for TeNPy
Topic: Initial product states
Replies: 1
Views: 317

Initial product states

Dear TeNPy members: I am asking how to set the initial product state for the DMRG simulation. For example, if we consider the following spin-1/2 1D Fermi-Hubbard chain: H = \sum_{i, \sigma} c_{i, \sigma}^\dagger c_{i+1, \sigma} + c_{i+1, \sigma}^\dagger c_{i, \sigma} + \sum_i n_{i,\uparrow} n_{i,\do...
by steven_tao
02 Apr 2020, 01:10
Forum: HowTos and FAQ for TeNPy
Topic: Define spin-1 Boson site
Replies: 1
Views: 2643

Define spin-1 Boson site

Dear Community, How we can define the spin-1 Boson site for the following Hamiltonian: H = - t \sum_{i, \sigma} \left(b^\dagger_{i, \sigma} b_{i+1, \sigma} + H.c. \right) + U_1 \sum_i n_{i, \sigma}\left(n_{i, \sigma}-1\right) + U_2 \sum_i \mathbf{S}_i^2 where spin operator \mathbf{S}_i = \sum_{\sigm...
by steven_tao
24 Mar 2020, 01:22
Forum: HowTos and FAQ for TeNPy
Topic: Adding disorders and adding a site to 1D SSH chain
Replies: 2
Views: 2531

Re: Adding disorders and adding a site to 1D SSH chain

Hi Johannes, it is greatly appreciated.
by steven_tao
24 Mar 2020, 01:20
Forum: HowTos and FAQ for TeNPy
Topic: 2D DMRG with boundary conditions and lattice index
Replies: 2
Views: 1293

Re: 2D DMRG with boundary conditions and lattice index

Hi Johannes, thank you very much. I got it.
by steven_tao
22 Mar 2020, 04:58
Forum: HowTos and FAQ for TeNPy
Topic: 2D DMRG with boundary conditions and lattice index
Replies: 2
Views: 1293

2D DMRG with boundary conditions and lattice index

Hi everyone: (1) I want to simulate a self-defined 2D lattice with Finite lattice sizes along both the x and y directions. I am not sure how to define the boundary conditions. Is it the right way to define the boundary condition like this: class Mylattice(lattice.Lattice): def __init__(self, Lx, Ly,...