The Computational Chemistry Comparison and Benchmark Database (CCCBDB) contains links to experimental and computational thermochemical data for a selected set of gas-phase atoms and molecules as well as tools for comparing experimental and computational ideal-gas thermochemical properties.
GAMESS-US is a full-featured electronic structure software package with MC-SCF, CC, DFT, and CI wave functions. QM/MM, FMO, solvation, and MD calculations are also possible.
NWChem is an electronic structure package that features MC-SCF, MPn, CC, CI, and DFT methods. Properties, solvation models, QM/MM, and MD simulations are also possible.
MOPAC (Molecular Orbital PACkage) is a semiempirical quantum chemistry program based on Dewar and Thiel's NDDO approximation. Available at this site are the open source version (OpenMOPAC) and information on the commerical version.
A database containing many publicly available Gaussian basis sets for quantum chemistry calculations, including literature references. The basis sets can be displayed in input formats suitable for a number of quantum chemistry programs.
"We're going to shoot an ultraviolet laser into a (special type of) crystal, and out will come two. lower-energy photons that are entangled," Cramer said. For the first phase of the experiment, to be started early next year, they will look for evidence of
Quantum computers would be able to process information in ways that standard computers cannot by tapping the unusual properties of quantum mechanics, but an analysis suggests that quantum computers would outclass conventional machines only by a slight degree for most computing problems, writes MIT professor Scott Aaronson. Evidence now indicates that quantum machines would be susceptible to many of the same algorithmic restrictions as classical computers, and these restrictions are totally independent of the practical problems of constructing quantum computers. A solid quantum computer algorithm would guarantee that computational paths leading to an incorrect answer neutralize while paths reading to a right answer reinforce, Aaronson says. The discovery of an efficient quantum algorithm to solve NP-complete problems remains elusive despite much effort, but one definite finding is that such an algorithm would have to efficiently take advantage of the problems' structure in a manner that is outside the capabilities of present-day methods. Aaronson points out that physicists have yet to come up with a final theory of physics, which gives rise to the possibility that a physical way to efficiently solve NP-complete problems may one day be revealed by a future theory. "People speculate about yet more powerful kinds of computers, some of which would make quantum computers look as pedestrian as vending machines," he notes. "All of them, however, would rely on speculative changes to the laws of physics." Aaronson projects that the difficulty of NP-complete problems will someday be perceived as a basic principle that describes part of the universe's fundamental nature.
IN 1999, legendary theoretical physicist Hans Bethe delivered three lectures on quantum theory to his neighbors at the Kendal of Ithaca retirement community (near Cornell University). Given by Professor Bethe at age 93, the lectures are presented here as
The import of the free will theorem is that it is notonly current quantum theory, but the world itself that is non-deterministic, so that no future theory can return us to a clockwork universe.
M. Elsen, B. Piest, F. Adam, O. Anton, P. Arciszewski, W. Bartosch, D. Becker, J. Böhm, S. Boles, K. Döringshoff and 30 other author(s). Microgravity Science and Technology, (Sep 7, 2023)Funding Information: The QUANTUS IV - MAIUS project is a collaboration of Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation Bremen, Leibniz Universität Hannover, Humboldt-Universität zu Berlin, Johannes Gutenberg-Universität Mainz and Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik. It is supported by the German Space Agency DLR with funds provided by the Federal Ministry for economic affairs and climate action (BMWK) under grant number DLR 50WP 1431-1435. We acknowledge support from Deutsches Zentrum für Luft- und Raumfahrt - Raumfahrtbetrieb, Oberpfaffenhofen, Deutsches Zentrum für Luft- und Raumfahrt - Simulations- und Softwaretechnik, Braunschweig. Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy - EXC-2123 QuantumFrontiers - 390837967.
D. Patel, and M. Wilde. (2023)cite arxiv:2307.14932Comment: 29 pages, 7 figures, published in the journal special issue dedicated to the memory of Göran Lindblad.