182 lines
7.5 KiB
C++
182 lines
7.5 KiB
C++
/**********************************************************
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This software is part of J.-S. Caux's ABACUS library.
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Copyright (c) J.-S. Caux.
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-----------------------------------------------------------
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File: ABACUS_LiebLin.h
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Purpose: Declares LiebLin gas-related classes and functions.
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***********************************************************/
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#ifndef ABACUS_LIEBLIN_H
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#define ABACUS_LIEBLIN_H
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#include "ABACUS.h"
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namespace ABACUS {
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// First, some global constants...
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const DP ITER_REQ_PREC_LIEBLIN = 1.0e+4 * MACHINE_EPS_SQ;
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const int LIEBLIN_Ix2_MIN = -1000000; // Like a UV cutoff. Assumption: never reached in scanning.
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const int LIEBLIN_Ix2_MAX = -LIEBLIN_Ix2_MIN;
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//***********************************************************************
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class LiebLin_Bethe_State {
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public:
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DP c_int; // interaction parameter
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DP L;
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DP cxL;
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int N;
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std::string label;
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Vect<int> Ix2_available; // quantum numbers which are allowable but not occupied
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Vect<int> index_first_hole_to_right;
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Vect<int> displacement;
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Vect<int> Ix2;
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Vect<DP> lambdaoc;
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Vect<DP> S; // scattering sum
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Vect<DP> dSdlambdaoc; // its derivative
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DP diffsq;
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DP prec;
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int conv;
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int iter_Newton;
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DP E;
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int iK;
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DP K;
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DP lnnorm;
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public:
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LiebLin_Bethe_State ();
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LiebLin_Bethe_State (DP c_int_ref, DP L_ref, int N_ref);
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LiebLin_Bethe_State& operator= (const LiebLin_Bethe_State& RefState);
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public:
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int Charge () { return(N); };
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void Set_to_Label (std::string label_ref, const Vect<int>& OriginStateIx2);
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void Set_to_Label (std::string label_ref); // assumes OriginState == GroundState
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void Set_Label_from_Ix2 (const Vect<int>& OriginStateIx2);
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void Set_Label_Internals_from_Ix2 (const Vect<int>& OriginStateIx2);
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bool Check_Admissibility(char whichDSF); // always returns true
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void Find_Rapidities (bool reset_rapidities);
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bool Check_Rapidities(); // checks that all rapidities are not nan
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DP String_delta(); // trivially returns 0; exists to mirror spin chain function
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bool Check_Symmetry (); // checks whether set of quantum numbers obeys { I } = { -I }
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void Compute_lnnorm ();
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void Compute_All (bool reset_rapidities); // solves BAE, computes E, K and lnnorm
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void Set_Free_lambdaocs();
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void Iterate_BAE(DP damping);
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void Iterate_BAE_S(DP damping);
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void Iterate_BAE_Newton(DP damping);
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void Compute_Energy ();
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void Compute_Momentum ();
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DP Kernel (int a, int b);
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DP Kernel (DP lambdaoc_ref);
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void Build_Reduced_Gaudin_Matrix (SQMat<DP>& Gaudin_Red);
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void Build_Reduced_BEC_Quench_Gaudin_Matrix (SQMat<DP>& Gaudin_Red);
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void Annihilate_ph_pair (int ipart, int ihole, const Vect<int>& OriginStateIx2);
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void Parity_Flip (); // takes all lambdaoc to -lambdaoc
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inline bool Set_to_Inner_Skeleton (int iKneeded, const Vect<int>& OriginIx2)
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{
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if (N < 3) ABACUSerror("N<3 incompatible with fixed momentum scanning");
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Ix2[0] = Ix2[1] - 2;
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Ix2[N-1] = Ix2[N-2] + 2;
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(*this).Compute_Momentum();
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if (iKneeded >= iK) Ix2[N-1] += 2*(iKneeded - iK);
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else Ix2[0] += 2*(iKneeded - iK);
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if (Ix2[0] < LIEBLIN_Ix2_MIN || Ix2[N-1] > LIEBLIN_Ix2_MAX) return(false);
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(*this).Set_Label_from_Ix2 (OriginIx2);
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return(true);
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}
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void Set_to_Outer_Skeleton (const Vect<int>& OriginIx2)
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{
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Ix2[0] = LIEBLIN_Ix2_MIN + (N % 2) + 1;
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Ix2[N-1] = LIEBLIN_Ix2_MAX - (N % 2) - 1;
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(*this).Set_Label_from_Ix2 (OriginIx2);
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};
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};
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inline bool Is_Inner_Skeleton (LiebLin_Bethe_State& State) {
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return (State.N >= 2 && (State.Ix2[0] == State.Ix2[1] - 2 || State.Ix2[State.N-1] == State.Ix2[State.N-2] + 2));
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};
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inline bool Is_Outer_Skeleton (LiebLin_Bethe_State& State) {
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return (State.N >= 2 && State.Ix2[0] == LIEBLIN_Ix2_MIN + (State.N % 2) + 1
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&& State.Ix2[State.N-1] == LIEBLIN_Ix2_MAX - (State.N % 2) - 1);
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};
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inline bool Is_Outer_Skeleton (const LiebLin_Bethe_State& State) {
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return (State.N >= 2 && State.Ix2[0] == LIEBLIN_Ix2_MIN + (State.N % 2) + 1
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&& State.Ix2[State.N-1] == LIEBLIN_Ix2_MAX - (State.N % 2) - 1);
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};
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inline bool Force_Descent (char whichDSF, LiebLin_Bethe_State& ScanState, LiebLin_Bethe_State& RefState,
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int desc_type_required, int iKmod, DP Chem_Pot)
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{
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bool forcedesc = false;
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// Force descent if we're computing density-density, we're at zero momentum and we're descending with momentum preserved:
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if (whichDSF == 'd' && ScanState.iK == RefState.iK && desc_type_required > 8) forcedesc = true;
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// For BEC to c > 0 quench, g2(x=0): force first step
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else if (whichDSF == 'B' && ScanState.label == RefState.label) forcedesc = true;
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else if (whichDSF == 'C' && ScanState.label == RefState.label) forcedesc = true;
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return(forcedesc);
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}
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std::ostream& operator<< (std::ostream& s, const LiebLin_Bethe_State& state);
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// FUNCTION DECLARATIONS:
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DP Chemical_Potential (LiebLin_Bethe_State& RefState);
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DP Sumrule_Factor (char whichDSF, LiebLin_Bethe_State& RefState, DP Chem_Pot, int iKmin, int iKmax);
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void Evaluate_F_Sumrule (char whichDSF, const LiebLin_Bethe_State& RefState, DP Chem_Pot,
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int iKmin, int iKmax, const char* RAW_Cstr, const char* FSR_Cstr);
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void Evaluate_F_Sumrule (std::string prefix, char whichDSF, const LiebLin_Bethe_State& RefState,
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DP Chem_Pot, int iKmin, int iKmax);
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void Evaluate_F_Sumrule (char whichDSF, DP c_int, DP L, int N, DP kBT, int nstates_req,
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DP Chem_Pot, int iKmin, int iKmax, const char* FSR_Cstr);
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// in LiebLin_Utils.cc
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DP LiebLin_dE0_dc (DP c_int, DP L, int N);
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DP LiebLin_vs (DP c_int, DP L, int N);
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DP LiebLin_Dressed_Charge_N (DP c_int, DP L, int N);
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int Momentum_Right_Excitations (LiebLin_Bethe_State& ScanState);
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int Momentum_Left_Excitations (LiebLin_Bethe_State& ScanState);
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DP ln_Overlap_with_BEC (LiebLin_Bethe_State& lambda);
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DP Particle_Hole_Excitation_Cost (char whichDSF, LiebLin_Bethe_State& AveragingState);
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std::complex<DP> ln_Density_ME (LiebLin_Bethe_State& lstate, LiebLin_Bethe_State& rstate);
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std::complex<DP> ln_Psi_ME (LiebLin_Bethe_State& lstate, LiebLin_Bethe_State& rstate);
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std::complex<DP> ln_g2_ME (LiebLin_Bethe_State& mu, LiebLin_Bethe_State& lambda);
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DP Compute_Matrix_Element_Contrib (char whichDSF, int iKmin, int iKmax, LiebLin_Bethe_State& LeftState,
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LiebLin_Bethe_State& RefState, DP Chem_Pot, std::stringstream& DAT_outfile);
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DP LiebLin_Twisted_lnnorm (Vect<std::complex<DP> >& lambdaoc, double cxL);
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std::complex<DP> LiebLin_Twisted_ln_Overlap (DP expbeta, Vect<DP> lstate_lambdaoc, DP lstate_lnnorm, LiebLin_Bethe_State& rstate);
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std::complex<DP> LiebLin_Twisted_ln_Overlap (std::complex<DP> expbeta, Vect<std::complex<DP> > lstate_lambdaoc, DP lstate_lnnorm, LiebLin_Bethe_State& rstate);
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std::complex<DP> LiebLin_ln_Overlap (Vect<DP> lstate_lambdaoc, DP lstate_lnnorm, LiebLin_Bethe_State& rstate);
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std::complex<DP> LiebLin_ln_Overlap (Vect<std::complex<DP> > lstate_lambdaoc, DP lstate_lnnorm, LiebLin_Bethe_State& rstate);
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// In src/LiebLin_Tgt0.cc:
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DP Entropy (LiebLin_Bethe_State& RefState);
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DP Canonical_Free_Energy (LiebLin_Bethe_State& RefState, DP kBT);
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LiebLin_Bethe_State Canonical_Saddle_Point_State (DP c_int, DP L, int N, DP kBT);
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LiebLin_Bethe_State Add_Particle_at_Center (const LiebLin_Bethe_State& RefState);
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LiebLin_Bethe_State Remove_Particle_at_Center (const LiebLin_Bethe_State& RefState);
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DP rho_of_lambdaoc_1 (LiebLin_Bethe_State& RefState, DP lambdaoc, DP delta);
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DP rho_of_lambdaoc_2 (LiebLin_Bethe_State& RefState, DP lambdaoc, DP delta);
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} // namespace ABACUS
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#endif
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