New measurements exceed Heisenberg uncertainty limit; is this experimental evidence for non-orthodox quantum theories?
Mar 26, 2017
The Heisenberg uncertainty principle is a key theoretical limit on the precision with which certain pairs of physical properties of a quantum state, such as position and momentum, can be known. In the Bohr-Heisenberg formulation of quantum theory, also known as the Copenhagen interpretation, the Heisenberg uncertainty principle is taken beyond a mere theoretical limit on the precision with which measurements can be made on quantum systems, and is instead interpreted as a fundamental property of the universe in which there is a certain level of intrinsic indeterminacy that places unsurpassable constraints on the degree of certainty with which any measurement of complementary variables can be made.
This of course, is according to the Bohr-Heisenberg theory of quantum mechanics, and essentially argues that the absolute uncertainty and irreducible limitations on the possibility to obtain certain knowledge about a quantum state reflects the inherent meaninglessness of actual, real particle states – like a path or trajectory. Because of this inherent uncertainty, what we classically regard as a particle literally takes every conceivable path, and is in every conceivable state -- it is a wavefunction in a superposition of states until one of a pair of variables is measured.
Now it appears that a recent experiment is throwing this idea of inherent quantum indeterminacy into question as another technique has been developed that can make measurements of complementary variables with precision exceeding the limit of Heisenberg indeterminacy. Researchers used laser light to link caesium atoms and a vibrating membrane. The research points to sensors capable of measuring movement with unseen precision beyond Heisenberg limits.
In a scientific report published in this week's issue of Nature, NBI-researchers - based on a number of experiments - demonstrate that Heisenberg's Uncertainty Principle to some degree can be neutralized. This has never been shown before, and the results may spark development of new measuring equipment as well as new and better sensors.
Professor Eugene Polzik, head of Quantum Optics (QUANTOP) at the Niels Bohr Institute, has been in charge of the research - which has included the construction of a vibrating membrane and an advanced atomic cloud locked up in a small glass cage.
… The idea behind the glass cell is to deliberately send the laser light used to study the membrane-movements on quantum level through the encapsulated atomic cloud BEFORE the light reaches the membrane, explains Eugene Polzik: "This results in the laser light-photons 'kicking' the object - i.e. the membrane - as well as the atomic cloud, and these 'kicks' so to speak cancel out. This means that there is no longer any Quantum Back Action - and therefore no limitations as to how accurately measurements can be carried out at quantum level"
This capability to exceed Heisenberg limits is demonstrating that the indeterminacy of the orthodox quantum model may not be intrinsic or fundamental in the way this is conventionally thought. Such a discovery is in support of other models of quantum theory, that contain all of the same explanatory power and agreement with experimentation as orthodox quantum theory but differ in the interpretation of the underlying mechanics.
The de Broglie-Bohm pilot wave theory is just such an interpretation that the International Space Federation often highlights as a superlative exemplar of a realist, deterministic, and nonlocal interpretation of quantum theory. In pilot wave theory, also known as Bohmian mechanics, quantum states, like particle trajectories, are real and in that sence deterministic. They evolve according to a universal wave function, meaning that the interaction of any one particle is influenced by the state-evolution of the entire universe. In this way, it is impossible to separate our measuring equipment (or ourselves) from the system being measured, hence there is always some degree of uncertainty in the measurement. This is not inherent, or intrinsic uncertainty, but instead can be surpassed with the right application, for instance using the recent method developed by the research team at the Niels Bohr Institute.