Recent advances in nanotechnology are
paving the way to attain control over individual microscopic objects. The
ability to prepare, manipulate, couple and measure single microscopic
systems facilitate the study of single quantum systems at the level of
individual events. Such experiments address the most fundamental aspects of
quantum theory.
Quantum theory gives us a recipe to compute the frequencies for observing
events only. As is well known from the early days of its development,
quantum theory does not describe individual events such as the arrival of a
single electron at a particular position on the detection screen.
Reconciling the mathematical formalism (that does not describe single
events) with the experimental fact that each observation yields a definite
outcome is often referred to as the quantum measurement paradox. It is the
most fundamental, unsolved problem in the foundation of quantum theory.
As the material presented on this web site demonstrates, it is possible to simulate quantum
phenomena on the level of individual events, without invoking a single
concept of quantum theory. This eventbyevent simulation approach
rigorously satisfies Einstein's criterion of local causality and builds up
the final outcome that agrees with quantum theory eventbyevent, just like
in real experiments.
Our simulation approach does not resolve the quantum
measurement paradox: It does not suffer from this problem. The averages that
can be computed from quantum theory are obtained through a simulation of
locally causal, classical (nonHamiltonian) dynamical systems. The key point
of these dynamical systems is that they are built from units that are
adaptive. Phrased differently, these units have a very primitive form of
learning capability and are called Deterministic Learning Machines (DLMs).
Results
Evidence that our eventbyevent simulation approach works is provided by
the successful application, that is by reproducing the averages predicted by
quantum theory, to:
 Doubleslit and twobeam interference experiments
with singlephotons
 Singlephoton beamsplitter and MachZehnder
interferometer experiments.
 Universal quantum computation.
 Quantum cryptography.
 Wheeler’s delayed choice experiment.
 Quantum eraser, singlephoton quantum optics in
general.
 EinsteinPodolskyRosenBohm experiments with
photons.
 EinsteinPodolskyRosenBohm experiments with
nonorthogonal detection planes.
Summary
 We have invented a systematic, modular procedure
to construct locally causal, classical (nonHamiltonian) dynamical
systems that can be used for a deterministic or pseudorandom
(unpredictable) eventbyevent simulation of realtime quantum
phenomena.
 Our simulation approach allows the modeling of
nanoscale processes on the level of individual events without using
concepts of quantum theory.
