Many-body Gibbs density matrix. More...
#include <DensityMatrix.hpp>
Public Member Functions | |
| DensityMatrix (StatesClassification const &S, Hamiltonian const &H, RealType beta) | |
| ~DensityMatrix ()=default | |
| Destructor. More... | |
| void | prepare () |
| Allocate memory for the parts. More... | |
| void | compute () |
| DensityMatrixPart const & | getPart (BlockNumber B) const |
| RealType | getWeight (QuantumState state) const |
| RealType | getAverageEnergy () const |
| Compute the average energy \( \langle E\rangle = \sum_s E_s w_s\). More... | |
| void | truncateBlocks (RealType Tolerance, bool verbose=true) |
| bool | isRetained (BlockNumber B) const |
 Public Member Functions inherited from Pomerol::Thermal | |
| Thermal (RealType beta) | |
| Public Member Functions inherited from Pomerol::ComputableObject | |
| ComputableObject ()=default | |
| StatusEnum | getStatus () const |
| Return the current computation status. More... | |
| void | setStatus (StatusEnum Status_in) |
Additional Inherited Members | |
| Public Types inherited from Pomerol::ComputableObject | |
| enum | StatusEnum { Constructed, Prepared, Computed } |
| Computation status of the object. More... | |
| Data Fields inherited from Pomerol::Thermal | |
| const RealType | beta |
| Inverse temperature \(\beta\). More... | |
| const ComplexType | MatsubaraSpacing |
| Spacing between (imaginary) Matsubara frequencies, \(i\pi/\beta\). More... | |
| Protected Attributes inherited from Pomerol::ComputableObject | |
| StatusEnum | Status = Constructed |
| Current computation status. More... | |
Detailed Description
Many-body Gibbs density matrix.
This class represents a many-body Gibbs density matrix
\[ \hat\rho = \frac{e^{-\beta\hat H}}{Z}, \quad Z = Tr[e^{-\beta\hat H}]. \]
The matrix is stored as a list of DensityMatrixPart (diagonal blocks), which correspond to invariant subspaces/diagonal blocks of the Hamiltonian \(\hat H\).
Definition at line 42 of file DensityMatrix.hpp.
Constructor & Destructor Documentation
◆ DensityMatrix()
| Pomerol::DensityMatrix::DensityMatrix | ( | StatesClassification const & | S, |
| Hamiltonian const & | H, | ||
| RealType | beta | ||
| ) |
Constructor.
- Parameters
-
[in] S Information about invariant subspaces of the Hamiltonian. [in] H The Hamiltonian \(\hat H\). [in] beta Inverse temperature \(\beta\).
◆ ~DensityMatrix()
|
default |
Destructor.
Member Function Documentation
◆ compute()
| void Pomerol::DensityMatrix::compute | ( | ) |
Compute statistical weights within every part (diagonal block).
- Precondition
- prepare() has been called.
◆ getAverageEnergy()
| RealType Pomerol::DensityMatrix::getAverageEnergy | ( | ) | const |
Compute the average energy \( \langle E\rangle = \sum_s E_s w_s\).
◆ getPart()
| DensityMatrixPart const& Pomerol::DensityMatrix::getPart | ( | BlockNumber | B | ) | const |
Return a reference to a part (diagonal block).
- Parameters
-
[in] B Index of the part.
◆ getWeight()
| RealType Pomerol::DensityMatrix::getWeight | ( | QuantumState | state | ) | const |
Return a statistical weight corresponding to a specified eigenstate.
- Parameters
-
[in] state Index of the eigenstate within the full Hilbert space.
◆ isRetained()
| bool Pomerol::DensityMatrix::isRetained | ( | BlockNumber | B | ) | const |
Does a given block contain any non-negligible statistical weights?
- Parameters
-
[in] B Index of the part (block).
◆ prepare()
| void Pomerol::DensityMatrix::prepare | ( | ) |
Allocate memory for the parts.
◆ truncateBlocks()
| void Pomerol::DensityMatrix::truncateBlocks | ( | RealType | Tolerance, |
| bool | verbose = true |
||
| ) |
Check if any of the statistical weights within each block is above a given tolerance. If not, mark the respective block as irrelevant (set the Retained flag to false).
- Parameters
-
[in] Tolerance Statistical weights smaller or equal to this value are considered negligible. [in] verbose Print out information about the truncation results.
The documentation for this class was generated from the following file:
- pomerol/DensityMatrix.hpp
