## Search found 9 matches

29 Jan 2023, 19:28
Forum: Algorithms
Topic: How do environments grow in infinite DMRG?
Replies: 2
Views: 16

### Re: How do environments grow in infinite DMRG?

Great explanation! One last question - is the canonical form preserved by making use of the Vidal notation? That is, while getting two-site "theta" tensor on sites L-1 and 0 we simply incorporate SL singular values into the (L-1)th tensor and SR into 0th tensor?
17 Jan 2023, 19:40
Forum: Algorithms
Topic: How are periodic boundary conditions implemented?
Replies: 1
Views: 110

### How are periodic boundary conditions implemented?

Hi! I was wondering, how the periodic boundary conditions are implemented in TeNPy? In some other post I've read, that the MPS never create loops, so how is this issue bypassed? By means of long range MPOs, or rather differently?
13 Oct 2021, 11:47
Forum: HowTos and FAQ for TeNPy
Topic: Different ways to run DMRG on a finite cylinder geometry
Replies: 2
Views: 1141

### Re: Different ways to run DMRG on a finite cylinder geometry

Thank you for the answer. That clarifies everything!
04 Oct 2021, 13:21
Forum: HowTos and FAQ for TeNPy
Topic: Different ways to run DMRG on a finite cylinder geometry
Replies: 2
Views: 1141

### Different ways to run DMRG on a finite cylinder geometry

Hi! I want to run a DMRG for a given model on a cylinder, and then compare the obtained results with the same model, but run on a torus. From what I understood from documentation, there is a couple of ways, in which I can obtain a cylinder geometry (examples for the Honecomb lattice and SpinModel): ...
22 Dec 2020, 20:07
Forum: HowTos and FAQ for TeNPy
Topic: How to obtain full spectrum of given Model?
Replies: 1
Views: 1764

### How to obtain full spectrum of given Model?

I want to obtain the full spectrum of some model and what is crucial - all MPSs representing all possible states. I believe, that for sufficiently large bond_dimension this shouldn't be a problem (at least for a small physical system). I wanted to use for this purpose DMRG, which is executed with an...
17 Dec 2020, 15:52
Forum: HowTos and FAQ for TeNPy
Topic: Relation between bond energies and total expected value of energy of MPS
Replies: 1
Views: 1730

### Relation between bond energies and total expected value of energy of MPS

I am running some tests using SpinChain. I obtained the ground states and a few excited ones using DMRG. Then, I calculated the expected value of energy of the whole MPS, and also bond energies: spinSite = SpinSite(S=0.5, conserve='Sz') lattice = Chain(L=N, site=spinSite) model_params = {...} model ...
14 Feb 2020, 15:25
Forum: HowTos and FAQ for TeNPy
Topic: How to calculate particular correlation function only between the nearest neighbors sites in my lattice?
Replies: 4
Views: 5817

### Re: How to calculate particular correlation function only between the nearest neighbors sites in my lattice?

Hi! Sorry for the long delay with my answer. I was just calculating something like $$\langle S_i^{+} S_j^{-}\rangle$$ for the nearest neighbors in a spin system
04 Feb 2020, 15:50
Forum: HowTos and FAQ for TeNPy
Topic: How to calculate particular correlation function only between the nearest neighbors sites in my lattice?
Replies: 4
Views: 5817

### Re: How to calculate particular correlation function only between the nearest neighbors sites in my lattice?

Hi! Thank you for the hint. I came up with the following function: # Returns list of MPS indices corresponding to coupled sites in the lattice def get_nearest_neighbors(lattice): neighbors = [] for u1, u2, dx in lattice.pairs['nearest_neighbors']: possible_couplings = lattice.possible_couplings(u1, ...
30 Jan 2020, 13:17
Forum: HowTos and FAQ for TeNPy
Topic: How to calculate particular correlation function only between the nearest neighbors sites in my lattice?
Replies: 4
Views: 5817

### How to calculate particular correlation function only between the nearest neighbors sites in my lattice?

Hi! I am trying to calculate some correlation functions ONLY between nearest neighbors in a Honeycomb lattice. If I use the "correlation_function()" from the "MPS" class I get an array of given correlation function between all sites in an MPS. How can I extract only the values th...