Zobrazeno 1 - 10
of 82
pro vyhledávání: '"Spencer, J. S."'
Quantum chemical calculations of the ground-state properties of positron-molecule complexes are challenging. The main difficulty lies in employing an appropriate basis set for representing the coalescence between electrons and a positron. Here, we ta
Externí odkaz:
http://arxiv.org/abs/2310.05607
Autor:
Cassella, G., Sutterud, H., Azadi, S., Drummond, N. D., Pfau, D., Spencer, J. S., Foulkes, W. M. C.
Deep neural networks have been extremely successful as highly accurate wave function ans\"atze for variational Monte Carlo calculations of molecular ground states. We present an extension of one such ansatz, FermiNet, to calculations of the ground st
Externí odkaz:
http://arxiv.org/abs/2202.05183
Autor:
Malone, Fionn D., Blunt, N. S., Brown, Ethan W., Lee, D. K. K., Spencer, J. S., Foulkes, W. M. C., Shepherd, James J.
Publikováno v:
Phys. Rev. Lett. 117, 115701 (2016)
Density matrix quantum Monte Carlo (DMQMC) is used to sample exact-on-average $N$-body density matrices for uniform electron gas systems of up to 10$^{124}$ matrix elements via a stochastic solution of the Bloch equation. The results of these calcula
Externí odkaz:
http://arxiv.org/abs/1602.05104
Publikováno v:
J. Chem. Phys. 144, 094110 (2016)
Within Full Configuration Interaction Quantum Monte Carlo, we investigate how the statistical error behaves as a function of the parameters which control the stochastic sampling. We define the inefficiency as a measure of the statistical error per pa
Externí odkaz:
http://arxiv.org/abs/1601.00865
Autor:
Coury, M. E. A., Dudarev, S. L., Foulkes, W. M. C., Horsfield, A. P., Ma, Pui-Wai, Spencer, J. S.
Publikováno v:
Phys. Rev. B 93, 075101 (2016)
Hubbard-like Hamiltonians are widely used to describe on-site Coulomb interactions in magnetic and strongly-correlated solids, but there is much confusion in the literature about the form these Hamiltonians should take for shells of p and d orbitals.
Externí odkaz:
http://arxiv.org/abs/1507.04613
Autor:
Malone, Fionn D., Blunt, N. S., Shepherd, James J., Lee, D. K. K., Spencer, J. S., Foulkes, W. M. C.
Publikováno v:
J. Chem. Phys. 143, 044116 (2015)
The recently developed density matrix quantum Monte Carlo (DMQMC) algorithm stochastically samples the N -body thermal density matrix and hence provides access to exact properties of many-particle quantum systems at arbitrary temperatures. We demonst
Externí odkaz:
http://arxiv.org/abs/1506.03057
Autor:
Blunt, N. S., Smart, Simon D., Kersten, J. A. F., Spencer, J. S., Booth, George H., Alavi, Ali
Publikováno v:
J. Chem. Phys. 142 (2015), 184107
We expand upon the recent semi-stochastic adaptation to full configuration interaction quantum Monte Carlo (FCIQMC). We present an alternate method for generating the deterministic space without a priori knowledge of the wave function and present sto
Externí odkaz:
http://arxiv.org/abs/1502.04847
Autor:
Spencer, J. S., Blunt, N. S., Vigor, W. A., Malone, F. D., Foulkes, W. M. C., Shepherd, James J., Thom, A. J. W.
Publikováno v:
Journal of Open Research Software, 3, e9, 2015
The HANDE quantum Monte Carlo project offers accessible stochastic algorithms for general use for scientists in the field of quantum chemistry. HANDE is an ambitious and general high-performance code developed by a geographically-dispersed team with
Externí odkaz:
http://arxiv.org/abs/1407.5407
Publikováno v:
J. Chem. Phys. 142, 104101 (2015)
We show that Full Configuration Interaction Quantum Monte Carlo (FCIQMC) is a Markov Chain in its present form. We construct the Markov matrix of FCIQMC for a two determinant system and hence compute the stationary distribution. These solutions are u
Externí odkaz:
http://arxiv.org/abs/1407.1753
We present a quantum Monte Carlo method capable of sampling the full density matrix of a many-particle system at finite temperature. This allows arbitrary reduced density matrix elements and expectation values of complicated non-local observables to
Externí odkaz:
http://arxiv.org/abs/1303.5007