MCTDHX forum
General MCTDHX Board => General Questions and Discussion => Topic started by: mctdhb on May 09, 2017, 11:49:36 AM

What MCTDHX is and what it can do
MCTDHX is a unique method that  roughly speaking  allows one to describe the way little particles behave according to quantum physics. The MCTDHX software is an implementation of that theory that allows to compute and visualize these quantum dynamics. Specifically, it is a way compute some fundamental properties of ensembles of indistinguishable particles, that is gases of atoms, that are constrained in a box or container at extremely low temperatures or electrons in atoms or molecules.
These properties can be collective, i.e., followed by all (or almost all) particles of the system or not. In the former case one is talking about a BoseEinstein condensate if the considered particles are indistinguishable bosons or uncorrelated fermions if the considered particles are indistinguishable fermions; in the latter case, the we speak about something more complicated, a socalled fragmented manyboson or a correlated manyfermion state. Indistinguishable bosons at low temperature or indistinguishable electrons in atoms or molecules behave quantummechanically: they are wavelike in nature and, hence, totally different than ordinary matter. In a BoseEinstein condensate (BEC), for instance, all the indistinguishable particles of the gas behave as if they were single effective particle.
Quantum fluctuations and correlations are negligible  such a behavior is referred to as coherent for bosons and singleconfigurational for fermions. However, there are many cases in which this not true, even at ultracold temperatures. Phenomena like fragmentation and correlations become very important. In such cases MCTDHX is applicable, but conventional meanfield descriptions fail. MCTDHX is designed to solve manybody dynamics of small and intermediate systems of ultracold particles (bosons or fermions) and shed light at phenomena where correlations emerge and meanfield approaches break down.
The fundamental physical equation that governs the evolution of atomic and quantum systems is the Schrödinger equation. MCTDHX is a method that can, in principle, describe these quantum dynamics exactly, i.e., to any desired given numerical accuracy, for a wide range of scenarios. To see more details about the MCTDHX method and software, just click here: http://ultracold.org/menu/ (http://ultracold.org/menu/)