FIZIKA A 15 (2006) 2 , 7384
A SIMPLE EXPERIMENTAL CHECK OF HEISENBERG'S UNCERTAINTY RELATIONS
SELIM PAŠIĆ^{a1,} OZREN GAMULIN^{b} and ZORAN TOCILJ^{a}
^{1}Email address: spasic@phy.hr
^{a}Department of Physics, Faculty of Science, University of Zagreb,
Bijenička 32, 10000 Zagreb, Croatia
^{b}School of Medicine, University of Zagreb, Šalata 3, 10000 Zagreb, Croatia
Received 15 May 2004; Revised manuscript received 31 January 2005
Accepted 21 March 2005 Online 10 November 2006
We show that the quantum mechanical interpretation of the diffraction
of light on a slit, when a wave function is assigned to a photon,
can be used for a direct experimental study of Heisenberg's
positionmomentum and equivalent positionwave vector uncertainty
relation for the photon. Results of an experimental test of the
positionwave vector uncertainty relation, where the wavelength is
used as the input parameter, are given and they very well confirm
our approach. The same experimental results can also be used for
a test of the positionmomentum uncertainty relation when the
momentum p_{0} of a photon is known as the input parameter. We show that
a measurement of p_{0}, independent of the knowledge of the value
of the Planck's constant, is possible. Using that value of p_{0},
a test of the positionmomentum uncertainty relation could be
regarded as a method for a direct measurement of the Planck's
constant. This is discussed, since the diffraction pattern is
also well described by classical electrodynamics in the considered
experimental conditions. This approach for testing the Heisenberg's
uncertainty relations is very simple and consequently suitable
as a quantitative exercise in undergraduate experimental courses,
as well as a visual and attractive demonstration of the Heisenberg's
uncertainty principle in courses of quantum mechanics.
PACS numbers: 01.50.Pa, 03.65.w
UDC 530.145, 535.14
Keywords: ethidium
