FIZIKA A 15 (2006) 2 , 73-84

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A SIMPLE EXPERIMENTAL CHECK OF HEISENBERG'S UNCERTAINTY RELATIONS

SELIM PAŠIĆa1, OZREN GAMULINb and ZORAN TOCILJa
1E-mail address: spasic@phy.hr

aDepartment of Physics, Faculty of Science, University of Zagreb, Bijenička 32, 10000 Zagreb, Croatia
bSchool 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 position-momentum and equivalent position-wave vector uncertainty relation for the photon. Results of an experimental test of the position-wave 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 position-momentum uncertainty relation when the momentum p0 of a photon is known as the input parameter. We show that a measurement of p0, independent of the knowledge of the value of the Planck's constant, is possible. Using that value of p0, a test of the position-momentum 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

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