Next month David J. Wineland, and Serge Haroche, will receive the Physics Nobel Prize, for their work in Quantum Manipulation.
With these physicists' work, we are closer to quantum computers, and other new applications of Quantum Mechanics. Mario Rabinowitz, since graduating from Washington State University with a Ph.D, has had a long, active career as a physicist, he recently published a paper that criticizes Bohr's interpretation of Quantum Mechanics, in particular the so-called Complementary Principle.
Rabinowitz shows that although Bohr’s Complementarity Principle claims that one cannot know two aspects of a quantum object, it is possible to do so at least for the so-called Wave-Particle Duality.
6.1 Violation of Complementarity
By means of a position measurement on an entangled idler particle, it was possible to determine the traversed slit in a Young’s two slit experiment, and still maintain the interference pattern. This violates Bohr’s complementarity principle  for the waveparticle duality. It is likely that this will open the floodgates for violation of Bohr’s complementarity principle in general. Varying parameters such as the distance from the source to the solitary screen, the distance from the source to the two-slit plate, the distance of the interference screen to the two-slit plate, the thickness of the two-slit plate, wavelength of the quantum particle, etc. may give further insight into the nature of entanglement.
6.2 de Broglie-Bohm Pilot-Wave
For the past six decades the Bohm modified pilot-wave theory of de Broglie, has been regarded as untestable with respect to the standard probabilistic interpretation of quantum mechanics. This is because both were regarded as always giving the same results, and Bohr’s wave-particle complementarity principle was largely expected to be inviolable. Now that complementarity has been violated, not only is the pilot-wave theory separately testable, but a host of challenges may be raised with respect to the probabilistic interpretation of quantum mechanics. However, both theories are nonlocal. Although the pilot-wave theory answers many questions, it also raises questions of its own such as: what is the wave made of; does it interact with all particles in the same way; is it restricted to be a probability wave because of its non-locality; etc.? Even before the pilot-wave, Einstein once considered the electromagnetic field as the guiding wave for photons. Although violation of complementarity is a data point in favor of the pilot-wave theory, other theories may still be consistent with the known data.
6.3 Violation of Probabilistic Quantum Theory
Menzel et al  conclude that their findings do not contradict standard probabilistic quantum theory that asserts that quantum wave states are not objectively real until actually measured. But on p. 9314 they say: “This result is surprising because which-slit information about the signal photon is ‘available’ and therefore the principle of complementarity suggests no interference.” Complementarity makes a much stronger statement in forbidding interference via an effectively collapsed signal photon vector state. If one of the wave functions collapses, this leaves no cross terms for interference. Contrary to their statement that this experiment demonstrates merely a surprising deviation of the probabilistic interpretation of quantum mechanics, it involves a major violation of that interpretation's basic principle. Saying that a body is in two mutually exclusive states at the same time until a measurement is made, is not the same thing as saying it is mathematically convenient to treat it as if the body were. Equal amplitude for both states can be assigned a priori or by a Bayesian approach."
Last century's most abstract advance in Physics: Quantum Mechanics is such, that I do not understand it yet. I know how to use Quantum Mechanics, but I do not know what it means.
I believe there is an actual field, we call this field the Wave Function. This object is not only mathematical, but has a reality of its own.
"I think that a particle must have a separate reality independent of the measurements. That is, an electron has spin, location and so forth even when it is not being measured. I like to think that the moon is there even if I am not looking at it.
Quote taken from Einstein Quotes