arXiv:1405.7873 · Physical Review A

Uncertainty in the context of multislit interferometry

Johannes C. G. Biniok, Paul Busch, Jukka Kiukas

Published Aug 22, 2014• 9 citations

Abstract

A pair of uncertainty relations relevant for quantum states of multislit interferometry is derived, based on the mutually commuting ``modular'' position and momentum operators and their complementary counterparts, originally introduced by Aharonov and co-workers. We provide a precise argument as to why these relations are superior to the standard Heisenberg uncertainty relation at expressing the complementarity between spatial localization and the appearance of fringes. We further support the argument with explicit computations involving wave functions specifically tailored to the interference setup. Conceptually developing the idea of Aharonov and co-workers, we show how the modular momentum should reflect the given experimental setup, yielding a refined observable that accurately captures the fine structure of the interference pattern.

DOI: 10.1103/physreva.90.022115

Related papers

Uncertainty formulations for multislit interferometry

Johannes C. G. Biniok

In the context of (far-field) multislit interferometry we investigate the utility of two formulations of uncertainty in accounting for the complementarity of spatial localization and fringe width. We begin with a characterization of the relevant observables and general considerations regarding the suitability of different types of measures. The detailed analysis shows that both of the discussed uncertainty formulations yield qualitatively similar results, confirming that they correctly capture the relevant tradeoff. One approach, based on an idea of Aharonov and co-workers, is intuitively appealing and relies on a modification of the Heisenberg uncertainty relation. The other approach, developed by Uffink and Hilgevoord for single- and double-slit experiments, is readily applied to multislits. However, it is found that one of the underlying concepts requires generalization and that the choice of the parameters requires more consideration than was known.

Physical Review ADec 22, 20140 citations

Compatible and incompatible observables in the paradigmatic multislit experiments of quantum mechanics

Johannes C. G. Biniok

The present investigation is about the quantum mechanics of multislit interference experiments. One of the cornerstones of our understanding of quantum mechanics is provided by the analysis of this type of experiments. Beginning with Bohr and Einstein, the discussion revolved mostly around single-slit diffraction and double-slit interference, probing the complementarity of path determination and the appearance of interference fringes, and contrasting the familiar with the quantum. Here, we are concerned with developing a systematic understanding and description of multislit interference experiments, i.e. setups in which a plurality of slits is illuminated. We provide a characterisation of a number of relevant observables, discussing those that are compatible and may be measured jointly, and also incompatible observables which cannot be measured jointly but instead display quantum uncertainty. \nWe begin with a discussion of a particular modification of the classic double- slit interference experiment which highlights the realisation of specific position and momentum observables which are jointly measurable. Although there are technical results regarding the coexistence of specific position and momentum observables, it may be surprising that ubiquitous experimental setups provide a preparation of such quantum states. We proceed with a discussion of the particular character of the incompatibility of certain measurements by building on an initial heuristic argument provided by Aharonov, Pendleton and Petersen. We prove, extend and discuss a formulation of un- certainty suitable for the context of multislit experiments. We conclude with a comparison of this formulation of uncertainty with an alternative uncertainty formulation developed by Uffink and Hilgevoord. Although these two uncertainty formulations are very different technically, we demonstrate that the same tradeoff is expressed independently.

Sep 1, 20140 citations

Multislit interferometry and commuting functions of position and momentum

Johannes C. G. Biniok, Paul Busch

In a recent, modified double-pinhole diffraction experiment the existence of an interference pattern was established indirectly along with a near-perfect imaging of the double pinhole. Our theoretical analysis shows that the experiment constitutes a preparation of a quantum state that is, to a good approximation, a joint eigenstate of commuting functions of position and momentum. Gaining information about the momentum distribution by means of the particular experimental setup is thus possible with negligible impact on the position distribution. Furthermore, we construct explicitly a class of states simultaneously localized on periodic sets in position and momentum space, which are therefore eigenstates of the observables being measured jointly (to a good approximation) in multislit interferometry. Finally, we show that with an appropriate change of settings the experiment demonstrates the mutual disturbance of position and momentum measurements.

arXiv:1303.7101Physical Review AJun 21, 20134 citations

Complementarity and uncertainty relations for matter-wave interferometry

Karl-Peter Marzlin, Barry C. Sanders, P. L. Knight

We establish a rigorous quantitative connection between (i) the interferometric duality relation for which-way information and fringe visibility and (ii) Heisenberg's uncertainty relation for position and modular momentum. We apply our theory to atom interferometry, wherein spontaneously emitted photons provide which-way information and unambiguously resolve the challenge posed by the metamaterial ``perfect lens'' to complementarity and to the Heisenberg-Bohr interpretation of the Heisenberg microscope thought experiment.

arXiv:0709.0613Physical Review ADec 9, 20088 citations

Complementarity and uncertainty in quantum interference

C. R. Shilladay

This thesis is concerned with the notions of complementarity and uncertainty encountered in quantum mechanics. Its starting point is an assessment of how these concepts have been represented and illustrated by various writers dating back to their inception. Following the survey a coherent account of the connections and contrasts between complementarity and uncertainty is developed in the context of Mach-Zehnder interferometry. The effect on the interference pattern contrast of path detection via entanglement with a probe system, is explored and a joint unsharp measurement scheme of the complementary pairs, path and interference, described. The Mach-Zehnder set-up proves sufficiently versatile to show that quantum erasure and quantitative quantum erasure constitute instances of joint unsharp measurement of complementary observables. The analysis uses the representation of observables as positive operator valued measures.Path detection and interference observation require different experimental set-ups but can be reconciled in the simultaneous unsharp measurement and preparation. This reconciliation is expressed as an uncertainty relation however the mutually exclusive feature of complementarity is not discarded. It is possible to recover strict complementarity as a limit case of the appropriate uncertainty relation.One motivation for this study is the effort some authors have made in trying to express the founding features of quantum mechanics in the form of a hierarchy of significance. Here it is shown that complementarity and uncertainty have separate identities but are not completely independent of each other. Consequently, establishing a hierarchy of these features within the present formalism of quantum mechanics is not possible.

Jan 1, 20070 citations

Complementarity and Uncertainty in Mach-Zehnder Interferometry and beyond

Paul Busch, C. R. Shilladay

A coherent account of the connections and contrasts between the principles of com-plementarity and uncertainty is developed starting from a survey of the various formalizations of these principles. The conceptual analysis is illustrated by means of a set of experimental schemes based on Mach-Zehnder interferometry. In particu-lar, path detection via entanglement with a probe system and (quantitative) quan-tum erasure are exhibited to constitute instances of joint unsharp measurements of complementary pairs of physical quantities, path and interference observables. The analysis uses the representation of observables as positive-operator-valued measures (POVMs). The reconciliation of complementary experimental options in the sense of simultaneous unsharp preparations and measurements is expressed in terms of uncertainty relations of different kinds. The feature of complementarity, manifest in the present examples in the mutual exclusivity of path detection and interference observation, is recovered as a limit case from the appropriate uncertainty relation. It is noted that the complementarity and uncertainty principles are neither completely logically independent nor logical consequences of one another. Since entanglement is an instance of the uncertainty of quantum properties (of compound systems), it is moot to play out uncertainty and entanglement against each other as possible mechanisms enforcing complementarity.

Jan 1, 200658 citations