Comp-phys-alps-users

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1244 discussions

Kondo lattice model
by Martin Hohenadler 10 Dec '13

10 Dec '13

Dear all, Taking the Kondo lattice model as an example which is included in the models.xml file, I was wondering how the distinction between the onsite exchange and the hopping is made. In terms of the Hamiltonian, there are sites with type 1 (itinerant fermions) and type 2 (local spins). However, both the hopping and the exchange are implemented in terms of bond operators acting between sites i and j, with the type of site not specified. Is that sufficient to ensure that the exchange … [View More]

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recompiling ALPS/looper for XYZ two-spin interaction calculations
by Nathanael Fortune 04 Dec '13

04 Dec '13

Does anyone have any advice on how to recompile the ALPS/looper package to support XYZ two-spin interactions (in addition to the already supported XXZ two-spin interactions)? A former student used the ALPS/looper packages support of XXZ two-spin interactions to carry out QMC calculations of the magnetic-field-dependent phase boundary for a S = 1/2 Heisenberg system with weak easy-plane (XY) anisotropy. Unfortunately for us, experiments experiments now reveal that the experimental system has a … [View More]weak but non-negligible biaxial asymmetry within the XY plane itself, necessitating the calculation of XYZ two-spin interactions that distinguish between X and Y. See background below for details, if curious. The Todo laboratory webpage for ALPS/Looper — see http://todo.issp.u-tokyo.ac.jp/en/projects/alps-looper?set_language=en/ — notes that the application can be recompiled to provide support for XYZ two-spin interactions but I haven't yet figured out how that can be done (nor how it would be re-integrated into the full ALPS package). I would appreciate any guidance this group can provide! Best Regards, Nat Fortune background: A colleague of mine used the ALPS/looper package to carry out QMC calculations of the magnetic-field-dependent phase boundary for a S = 1/2 Heisenberg system with weak easy-plane (XY) anisotropy. He did this by setting the spin-Hamiltonian parameters Jz/Jxy = 0.995. This corresponds to $\frac{\Delta}{J} = 0.005$, where the Hamiltonian is given by the following equation: \begin{equation} H = J \sum_{nn}[S_{i}^{x} S_{j}^{x}+ S_{i}^{y} S_{j}^{y} + ( 1 -\Delta ) S_{i}^{z} S_{j}^{z}] + J_{\perp}\sum_{i,i'} \boldsymbol{S}_{i} \cdot \boldsymbol{S}_{i'}-g \mu_B \boldsymbol{H}\cdot \sum_{j}\boldsymbol{S}_j \label{eq:Xiao2009Hamiltonian} \end{equation} and the first summation is over nearest neighbors, the second summation links each spin to its counterparts in adjacent layers, and the third summation includes all spins. Unfortunately for us, experiments now reveal that the experimental system we want to model is better described by a biaxial asymmetry within the XY plane, where $\Delta = 0.003$ would be replaced by $\Delta_{z} = 0.003$ and $\Delta_{y} = 0.0003$, where the Hamiltonian is given by the following equation: \begin{equation} H = J \sum_{i,j}[S_{i}^{x} S_{j}^{x}+ ( 1 -\Delta_y ) S_{i}^{y} S_{j}^{y} + ( 1 -\Delta_z ) S_{i}^{z} S_{j}^{z}] -g \mu_B \boldsymbol{H}\cdot \sum_{j}\boldsymbol{S}_j + J_{\perp}\sum_{i,i'} \boldsymbol{S}_{i} \cdot \boldsymbol{S}_{i'} \label{eq:NewHamiltonian} \end{equation} -- Professor Nathanael Fortune, Ph.D. Department of Physics 315 McConnell Hall 44 College Lane Smith College Northampton MA 01063 nfortune(a)smith.edu (413) 585-3980 (office) (413) 585-3919 (lab) http://www.smith.edu/physics/ "The great tragedy of Science — the slaying of a beautiful hypothesis by an ugly fact." T.H. Huxley [View Less]

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Question about CONSERVED_QUANTUMNUMBERS in DMRG code
by Rafał 18 Nov '13

18 Nov '13

Dear all ALPS users, I have following questions to the DMRG tutorials. Why there is N in a line: 'CONSERVED_QUANTUMNUMBERS' : 'N,Sz', I understand that Sz stands for conserved quantum number but spin model on the open chain lattice does not have quantum number called N. Is this N added to 'CONSERVED_QUANTUMNUMBERS' just in case someone may use some bosonic model? Bests, Rafał

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poor performance of DMRG on Ising chain
by Emanuele Levi 15 Nov '13

15 Nov '13

Dear ALPS users, I am checking the performance of the DMRG application of ALPS on a simple Ising chain with periodic boundary conditions. The program seems not to be able to converge to the right ground state, even for lengths of the chain such as L=6,8,.. Comparing to the results of the sparsdiag algorithm included in the package the ground state energies are very different. Does anyone know why it is so? Any idea on how to overcome this problem? Thank you in advance. -- Dr Emanuele Levi emanuele.levi(a)gmail.com

2 4

compile alps on cray xc30 machine
by Jia Chen 15 Nov '13

15 Nov '13

Hello, I am new to alps. Now I am trying to compile the code on a cray xc30 machine. Following the procedure on website. But when I compile by make, I always get error message "/usr/bin/ld: attempted static link of dynamic object `../src/alps/libalps.so.2.2.b1' make[2]: *** [tool/archive] Error 1" I hope some one here has experience of dealing with this type of problem and can help me out here. Regards -- Jia Chen

2 1

Saving one parameter / Observables in Python
by Peter Bröcker 11 Nov '13

11 Nov '13

Good morning, I have two questions that I could not find an answer to. In my simulation, I would like to save one or more parameter that I adjust while it's running. This parameter is not an observable, but I could of course pretend that it is and save only one value. I am wondering though if there is not a more elegant way to handle this. My other question is related to the analysis of data. I would like to know how many entries a given observable has. In my code, I use the RealObservable … [View More]

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s-wave pair field correlation function in fullED
by Vladimir Iglovikov 09 Nov '13

09 Nov '13

[1] I am trying to compute s-wave pair field correlation function, using full diagonalization routine for the fermionic Hubbard model. This function is defined as: P_s = \langle \Delta^{\dagger} \Delta + \Delta \Delta^{\dagger} \rangle, where \Delta^{\dagger} = \frac {1} {\sqrt{N}} \sum_{k} c^{\dagger}_{n \uparrow} c^{\dagger}_{n \downarrow} And I can not figure out how to measure this. [2] How do I measure Kinetic energy? When I am trying use: 'MEASURE_AVERAGE[kinetic-energy]' : '… [View More]fermion_kinetic_energy' I get error: Cannot evaluate expression 0.333333 * fermion_kinetic_energy(i) Here is my model definition: ------------------------------ <MODELS> <SITEBASIS name="fermion"> <QUANTUMNUMBER name="Nup" min="0" max="1" type="fermionic"/> <QUANTUMNUMBER name="Ndown" min="0" max="1" type="fermionic"/> <OPERATOR name="Splus" matrixelement="1"> <CHANGE quantumnumber="Ndown" change="-1"/> <CHANGE quantumnumber="Nup" change="1"/> </OPERATOR> <OPERATOR name="Sminus" matrixelement="1"> <CHANGE quantumnumber="Nup" change="-1"/> <CHANGE quantumnumber="Ndown" change="+1"/> </OPERATOR> <OPERATOR name="Sz" matrixelement="(Nup-Ndown)/2"/> <OPERATOR name="Nup" matrixelement="Nup"/> <OPERATOR name="Ndown" matrixelement="Ndown"/> <OPERATOR name="N" matrixelement="Nup+Ndown"/> <OPERATOR name="c_down" matrixelement="1"> <CHANGE quantumnumber="Ndown" change="-1"/> </OPERATOR> <OPERATOR name="cdag_down" matrixelement="1"> <CHANGE quantumnumber="Ndown" change="1"/> </OPERATOR> <OPERATOR name="c_up" matrixelement="1"> <CHANGE quantumnumber="Nup" change="-1"/> </OPERATOR> <OPERATOR name="cdag_up" matrixelement="1"> <CHANGE quantumnumber="Nup" change="1"/> </OPERATOR> <OPERATOR name="n" matrixelement="Nup+Ndown"/> <OPERATOR name="n_up" matrixelement="Nup"/> <OPERATOR name="n_down" matrixelement="Ndown"/> <OPERATOR name="double_occupancy" matrixelement="Nup*Ndown"/> </SITEBASIS> <BONDOPERATOR name="fermion_hop" source="x" target="y"> cdag_up(x)*c_up(y)+cdag_up(y)*c_up(x)+cdag_down(x)*c_down(y)+cdag_down(y)*c_down(x) </BONDOPERATOR> <GLOBALOPERATOR name="fermion_kinetic_energy"> <BONDTERM type="0" source="i" target="j"> -t*fermion_hop(i,j) </BONDTERM> </GLOBALOPERATOR> <BASIS name="fermion"> <SITEBASIS type="1" ref="fermion"/> <SITEBASIS type="2" ref="fermion"/> <SITEBASIS type="3" ref="fermion"/> <CONSTRAINT quantumnumber="Nup" value="Nup_total"/> <CONSTRAINT quantumnumber="Ndown" value="Ndown_total"/> <CONSTRAINT quantumnumber="N" value="N_total"/> <CONSTRAINT quantumnumber="Sz" value="Sz_total"/> </BASIS> <HAMILTONIAN name="fermionic Hubbard"> <PARAMETER name="mu" default="0"/> <PARAMETER name="t" default="1"/> <PARAMETER name="U" default="0"/> <BASIS ref="fermion"/> <SITETERM site="i"> <PARAMETER name="mu#" default="mu"/> <PARAMETER name="U#" default="U"/> +U# * (n_up(i) - 0.5) * (n_down(i) - 0.5) - mu# * n(i) </SITETERM> <BONDTERM source="i" target="j"> -t*fermion_hop(i, j) </BONDTERM> </HAMILTONIAN> </MODELS> ----------------------- Lattice definition: ----------------------- <LATTICES> <LATTICE name="square" dimension="2"> <PARAMETER name="a" default="1"/> <BASIS> <VECTOR> a 0 </VECTOR> <VECTOR> 0 a </VECTOR> </BASIS> <RECIPROCALBASIS> <VECTOR>2*pi/a 0</VECTOR> <VECTOR>0 2*pi/a</VECTOR> </RECIPROCALBASIS> </LATTICE> <UNITCELL name="Lieb" dimension="2"> <VERTEX id="1" type="1"> <COORDINATE>0 0</COORDINATE> </VERTEX> <VERTEX id="2" type="2"> <COORDINATE>0.5 0</COORDINATE> </VERTEX> <VERTEX id="3" type="3"> <COORDINATE>0 0.5</COORDINATE> </VERTEX> <EDGE> <SOURCE vertex="1" offset="0 0"/> <TARGET vertex="2" offset="0 0"/> </EDGE> <EDGE> <SOURCE vertex="1" offset="0 0"/> <TARGET vertex="3" offset="0 0"/> </EDGE> <EDGE> <SOURCE vertex="1" offset="1 0"/> <TARGET vertex="2" offset="0 0"/> </EDGE> <EDGE> <SOURCE vertex="1" offset="0 1"/> <TARGET vertex="3" offset="0 0"/> </EDGE> </UNITCELL> <LATTICEGRAPH name="Lieb" vt_skip="true"> <FINITELATTICE> <LATTICE ref="square"/> <EXTENT dimension="1" size="nx"/> <EXTENT dimension="2" size="ny"/> <BOUNDARY type="periodic" /> </FINITELATTICE> <UNITCELL ref="Lieb"/> </LATTICEGRAPH> </LATTICES> [View Less]

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dmrg with complex hopping amplitudes
by benoît grémaud 28 Oct '13

28 Oct '13

Dear All, I'm using DMRG (bose-hubbard) with complex tunneling amplitudes, the hamiltonian being hermitian, of course. The results in simple situation is reasonable, i.e. the energy and local density are invariant by local U(1) transformation. In addition, I am measuring the ODLRO, i.e. I have the following line in the input file: 'MEASURE_CORRELATIONS[ODLRO]' : "bdag:b", However, the results are always real numbers, whereas I would expect complex numbers. Do they correspond to the real part … [View More]

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Error Installation in Ubuntu 12.04 Lts(64 bit)
by Javad Vahedi 26 Oct '13

26 Oct '13

Dear Michele Many thanks for your consideration. Heres my output ######################################################## maha@maha-pc:~/Downloads/build$ cmake . -- Compiler version: c++ (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3 -- Build type: Release -- Python interpreter /usr/bin/python -- Python interpreter ok : version 2.7.3 -- PYTHON_INCLUDE_DIRS = /usr/include/python2.7 -- PYTHON_NUMPY_INCLUDE_DIR = /usr/lib/python2.7/dist -packages/numpy/core/include -- PYTHON_SITE_PKG = /usr/lib/python2.… [View More]7/dist-packages -- PYTHON_LIBRARY = /usr/lib/python2.7/config/libpython2.7.so -- PYTHON_EXTRA_LIBS =-lssl -lcrypto -lssl -lcrypto -L/usr/lib -lz -lpthread -ldl -lutil -- PYTHON_LINK_FOR_SHARED = -Xlinker -export-dynamic -Wl,-O1 -Wl, -Bsymbolic-functions -- ALPS version: 2.2.b1 -- Looking for Boost Source -- Found Boost Source: /home/maha/Downloads/alps-2.2.b1-r7195-src -with-boost/boost -- Boost Version: 1_54_0 -- Adding Boost dir: /home/maha/Downloads/alps-2.2.b1-r7195-src -with-boost/boost -- MPI compiler was /usr/bin/mpicxx -- LAPACK DEBUG::Compiler id GNU -- LAPACK DEBUG::Compiler version -- LAPACK DEBUG::Processor x86_64 -- LAPACK DEBUG::ENV{MKL} -- LAPACK DEBUG::ENV{MKLROOT} /opt/intel/composer_xe_2013.5.192/mkl -- LAPACK DEBUG::ENV{MKL_HOME} -- LAPACK DEBUG::MKL_VERSION (raw) 2013.5.192 -- LAPACK DEBUG::MKL_VERSION 10.3.1 -- Found intel/mkl library -- LAPACK DEBUG::LAPACK_LIBRARY = -L/opt/intel/composer_xe_2013.5.192/mkl/lib/intel64;-lmkl_intel_lp64;-lmkl_sequential;-lmkl_core;-lpthread;-lm -- SQLite Library: not found -- LPSolve Library: not found -- Could NOT find SZIP (missing: SZIP_LIBRARIES SZIP_INCLUDE_DIRS) -- HDF5: /usr/include debug;/usr/lib/libhdf5_hl.so;/usr/lib/libhdf5.so;optimized;/usr/lib/libhdf5_hl.so;/usr/lib/libhdf5.so HDF5_DLL-NOTFOUND;HDF5_HL_DLL-NOTFOUND -- Python interpreter /usr/bin/python -- Python interpreter ok : version 2.7.3 -- PYTHON_INCLUDE_DIRS = /usr/include/python2.7 -- PYTHON_NUMPY_INCLUDE_DIR = /usr/lib/python2.7/dist -packages/numpy/core/include -- PYTHON_SITE_PKG = /usr/lib/python2.7/dist-packages -- PYTHON_LIBRARY = /usr/lib/python2.7/config/libpython2.7.so -- PYTHON_EXTRA_LIBS =-lssl -lcrypto -lssl -lcrypto -L/usr/lib -lz -lpthread -ldl -lutil -- PYTHON_LINK_FOR_SHARED = -Xlinker -export-dynamic -Wl,-O1 -Wl, -Bsymbolic-functions -- Numpy include in /usr/lib/python2.7/dist-packages/numpy/core/include -- ALPS XML dir is /opt/alps/lib/xml -- HDF5: /usr/include debug;/usr/lib/libhdf5_hl.so;/usr/lib/libhdf5.so;optimized;/usr/lib/libhdf5_hl.so;/usr/lib/libhdf5.so HDF5_DLL-NOTFOUND;HDF5_HL_DLL-NOTFOUND;HDF5_DLL-NOTFOUND;HDF5_HL_DLL-NOTFOUND -- HDF5: /usr/include debug;/usr/lib/libhdf5_hl.so;/usr/lib/libhdf5.so;optimized;/usr/lib/libhdf5_hl.so;/usr/lib/libhdf5.so HDF5_DLL-NOTFOUND;HDF5_HL_DLL-NOTFOUND;HDF5_DLL-NOTFOUND;HDF5_HL_DLL-NOTFOUND -- tebd will not be built -- HDF5: /usr/include debug;/usr/lib/libhdf5_hl.so;/usr/lib/libhdf5.so;optimized;/usr/lib/libhdf5_hl.so;/usr/lib/libhdf5.so HDF5_DLL-NOTFOUND;HDF5_HL_DLL-NOTFOUND;HDF5_DLL-NOTFOUND;HDF5_HL_DLL-NOTFOUND -- Configuring done -- Generating done -- Build files have been written to: /home/maha/Downloads/build #################################################################### Your sincerely Javad [View Less]

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dmrg with complex tunneling
by benoît grémaud 26 Oct '13

26 Oct '13

1 0

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Comp-phys-alps-users