## Search found 12 matches

- 07 Jul 2020, 13:15
- Forum: HowTos and FAQ for TeNPy
- Topic: Multiple sites to combine charges
- Replies:
**1** - Views:
**742**

### Multiple sites to combine charges

Hi TeNPy community, If I have a 1D chain, each unit cell contains three sublattices: two bosons and one spin. "Two bosons" here refers to one boson with pseudo spins (or two species bosons). In the simulation, I want to fix the number of both bosons (For each boson, we set a fixed number, ...

- 10 Jun 2020, 00:47
- Forum: HowTos and FAQ for TeNPy
- Topic: overlap of ground states at different parameters
- Replies:
**5** - Views:
**1430**

### 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 ...

- 09 Jun 2020, 23:45
- Forum: HowTos and FAQ for TeNPy
- Topic: overlap of ground states at different parameters
- Replies:
**5** - Views:
**1430**

### 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...

- 09 Jun 2020, 11:29
- Forum: HowTos and FAQ for TeNPy
- Topic: overlap of ground states at different parameters
- Replies:
**5** - Views:
**1430**

### 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...

- 08 Jun 2020, 23:49
- Forum: HowTos and FAQ for TeNPy
- Topic: Adding a site to a chain perpendicularly
- Replies:
**6** - Views:
**2843**

### Re: Adding a site to a chain perpendicularly

I got it, thanks.

- 08 Jun 2020, 23:00
- Forum: HowTos and FAQ for TeNPy
- Topic: Adding a site to a chain perpendicularly
- Replies:
**6** - Views:
**2843**

### 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....

- 22 May 2020, 11:31
- Forum: HowTos and FAQ for TeNPy
- Topic: Initial product states
- Replies:
**1** - Views:
**1005**

### 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...

- 02 Apr 2020, 01:10
- Forum: HowTos and FAQ for TeNPy
- Topic: Define spin-1 Boson site
- Replies:
**1** - Views:
**3311**

### 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...

- 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:
**25771**

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

Hi Johannes, it is greatly appreciated.

- 24 Mar 2020, 01:20
- Forum: HowTos and FAQ for TeNPy
- Topic: 2D DMRG with boundary conditions and lattice index
- Replies:
**2** - Views:
**2092**

### Re: 2D DMRG with boundary conditions and lattice index

Hi Johannes, thank you very much. I got it.

- 22 Mar 2020, 04:58
- Forum: HowTos and FAQ for TeNPy
- Topic: 2D DMRG with boundary conditions and lattice index
- Replies:
**2** - Views:
**2092**

### 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,...

- 15 Mar 2020, 06:32
- Forum: HowTos and FAQ for TeNPy
- Topic: Adding disorders and adding a site to 1D SSH chain
- Replies:
**2** - Views:
**25771**

### Adding disorders and adding a site to 1D SSH chain

Hello, TeNPy community, I want to simulate the following Boson-Hubbard Hamiltonian on a simple SSH chain: H = \sum_i \left(t_1 b_i^\dagger a_i + t_2 a_{i+1}^\dagger b_i + H.c.\right) + \sum_i (U_1 a_i^\dagger a_i a_i^\dagger a_i + U_2 b_i^\dagger b_i b_i^\dagger b_i) + \sum_i (V_i a_i^\dagger a_i + ...