Decoherence Cross-Section in NO + Ar Collisions: Experimental Results and a Simple Model

Abstract

Quantum decoherence can be viewed as the mechanism responsible for the quantum-to-classical transition as the initially prepared quantum state interacts with its environment in an irreversible manner. One of the most common mechanisms responsible for the macroscopically observed decoherence involves collisions of an atom or molecule, initially prepared in a coherent superposition of states, with gas particles. In this work, a coherent superposition of quantum internal states of NO molecules is prepared by the interaction between the molecule with both a static and a radiofrequency electric field. Subsequently, NO + Ar collision decoherence experiments are investigated by measuring the loss of coherence as a function of the number of collisions. Data analysis using a model based on the interaction potential of the collisional partners allowed to unravel the molecular mechanism responsible for the loss of coherence in the prepared NO quantum superposition of internal states. The relevance of the present work relies on several aspects. On the one hand, the use of radio-waves introduces a new way for the production of coherent beams. On the other hand, the employed methodology could be useful in investigating the Stereodynamics of chemical reactions with coherent reagents.

Coordinate Analysis for Interpreting the Decoherence in the Coherent NO with Ar Collision: A Physico-mathematical Picture Using the Stereographic Projection and the Cusp Catastrophe

“…Ureña and coworkers measured an unexpectedly large NO decoherence cross‐section with Ar collision while preparing the coherent NO molecular beam. They used radio frequency (RF) and a static DC field for producing the coherent NO beam and measured the visibility V of the coherent NO beam intensity as a function of Ar gas pressure in the scattering cell . The visibility is defined by Eq.…”

“…in the next section.) Thus, quantum decoherence cross‐section becomes observable . A comparison was made between the decoherence collision cross‐section ( σ d = 2.58 × 10 3 Å 2 ) and its attenuation cross‐section ( σ att = 230 Å 2 ), and an unexpectedly large difference between the two cross‐sections was found, as schematically shown in Figure .…”

“…Recently, Ureña coworkers performed an experiment on the NO collisional decoherence cross‐section measurement in the NO + Ar system . They used radio waves with a static DC field for producing a coherent NO molecular beam and measured the visibility of the coherent NO beam intensity as a function of Ar pressure in the scattering cell.…”