Questions tagged [quantum-dynamics]

Questions about quantum dynamics methods (MCTDH, t-DMRG, Feynman integral dynamics, etc.), or in some cases about quantum dynamics itself. Quantum dynamics is usually the dynamics of wavefunctions, density matrices, reduced density matrices, Wigner functions, or properties/expectation-values.

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5
votes
1answer
126 views

How to calculate state population from MCTDH?

In this reference, the author investigates electronic population dynamics from a MCTDH calculation. My question is how to generate state populations over time from an MCTDH calculation? Is there a ...
11
votes
1answer
222 views

What are some of the biggest theoretical and computational challenges in Condensed Phase Chemistry?

What are some of the biggest open-questions / challenges in Condensed Phase theory and computation? What efforts are being done to answer them? I realize Condensed Phase chemistry is a huge field, but ...
12
votes
1answer
322 views

How exact is DFT, really?

It is often claimed (e.g. here), that Density Functional Theory is in principle exact. This seems to be a very strong statement to me. Are all current limitations only of a technical nature rather ...
18
votes
4answers
586 views

References for Molecular Dynamics?

I am new to the world of Molecular Dynamics (zero practical experience), and I know that a starting point to really go into the back-bone of MD is Statistical Mechanics (took a semester course in ...
8
votes
1answer
120 views

What is the “overcoherence problem” in Ehrenfest dynamics?

I am a novice in Ehrenfest dynamics and would like to know why Ehrenfest dynamics suffers from the "overcoherence problem"?
5
votes
0answers
56 views

What is the difference between Ehrenfest dynamics and Born-Oppenheimer Molecular Dynamics? [duplicate]

What is the fundamental difference(s) between Ehrenfest dynamics and Born-Oppenheimer MD? Also, in what situation(s) or case(s) one is preferred than the other one?
9
votes
1answer
111 views

What are the types of Quantum Molecular Dynamics (QMD)?

In similar spirit to recent questions on Quantum Monte Carlo, ab-initio Molecular Dynamics, types of SCF, and others, I would like to ask: What are the types of Quantum Molecular Dynamics (QMD)? As I ...
19
votes
1answer
142 views

Quadrature over three Euler Angles for orientation averaging

Does anybody know about an accurate quadrature rule over three Euler angles $\theta, \phi, \chi$? I am trying to calculate the average value of an arbitrary function $f(\theta, \phi, \chi)$ for a ...
6
votes
2answers
139 views

How is MCTDH derived?

In the multi-configurational time-dependent Hartree (MCTDH) method, the equation of motion is derived from the time-dependent Schrödinger equation by substituting the wavefunction ansatz expanded in a ...
9
votes
1answer
132 views

How to construct the single particle function (SPF) basis in MCTDH?

In the multi-configurational time-dependent Hartree (MCTDH) theory, one essential step that reduces the memory and time cost is to form a single particle function (SPF) basis ansatz as shown in ...