No qualms about quantum theory

Nov 26, 2013

A colloquium paper published in European Physical Journal D looks into the alleged issues associated with quantum theory. Berthold-Georg Englert from the National University of Singapore reviews a selection of the potential problems of the theory. In particular, he discusses cases when mathematical tools are confused with the actual observed sub-atomic scale phenomena they are describing. Such tools are essential to provide an interpretation of the observations, but cannot be confused with the actual object of studies.

The author sets out to demystify a selected set of objections targeted against in the literature. He takes the example of Schrödinger's infamous cat, whose vital state serves as the indicator of the occurrence of , whereby the decay triggers a hammer mechanism designed to release a lethal substance. The term 'Schrödinger's cat state' is routinely applied to superposition of so-called quantum states of a particle. However, this imagined superposition of a dead and live cat has no reality. Indeed, it confuses a physical object with its description. Something as abstract as the wave function − which is a mathematical tool describing the quantum state − cannot be considered a material entity embodied by a cat, regardless of whether it is dead or alive.

Other myths debunked in this paper include the provision of proof that quantum theory is well defined, has a clear interpretation, is a local theory, is not reversible, and does not feature any instant action at a distance. It also demonstrates that there is no measurement problem, despite the fact that the measure is commonly known to disturb the system under measurement. Hence, since the establishment of quantum theory in the 1920s, its concepts are now clearer, but its foundations remain unchanged.

Explore further: The importance of three-way atom interactions in maintaining coherence

More information: B.G. Englert (2013), On Quantum Theory, European Physical Journal D, DOI: 10.1140/epjd/e2013-40486-5

Related Stories

Does probability come from quantum physics?

Feb 05, 2013

(Phys.org)—Ever since Austrian scientist Erwin Schrodinger put his unfortunate cat in a box, his fellow physicists have been using something called quantum theory to explain and understand the nature of waves and particles.

Physicists 'uncollapse' a partially collapsed qubit

Nov 11, 2013

(Phys.org) —One of the striking features of a qubit is that, unlike a classical bit, it can be in two states at the same time. That is, until a measurement is made on the qubit, causing it to collapse into ...

Recommended for you

Quantum physics just got less complicated

Dec 19, 2014

Here's a nice surprise: quantum physics is less complicated than we thought. An international team of researchers has proved that two peculiar features of the quantum world previously considered distinct ...

Controlling light on a chip at the single-photon level

Dec 16, 2014

Integrating optics and electronics into systems such as fiber-optic data links has revolutionized how we transmit information. A second revolution awaits as researchers seek to develop chips in which individual ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

carl_badgley
1 / 5 (1) Nov 26, 2013
as a total nonprofessional, i have often wondered if what we are waiting for is not a new maths that can better explain quantum phenomenon.
Non-on
3 / 5 (2) Nov 27, 2013
The abstract says:

Quantum theory is a well-defined local theory with a clear interpretation. No "measurement problem" or any other foundational matters are waiting to be settled.

I think that's false; the foundational issues are complex and difficult. Interested readers should see:

plato.stanford.edu/entries/qt-measurement/

which says,

From the inception of Quantum Mechanics (QM) the concept of measurement proved a source of difficulties that found concrete expression in the Einstein-Bohr debates, out of which both the Einstein Podolsky Rosen paradox and Schrödinger's cat paradox developed. In brief, the difficulties stemmed from an apparent conflict between several principles of the quantum theory of measurement. In particular, the linear dynamics of quantum mechanics seemed to conflict with the postulate that during measurement a non-linear collapse of the wave packet occurred.

and also:

plato.stanford.edu/entries/qm-copenhagen/
plato.stanford.edu/entries/qm-manyworlds/

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.