title: Real-time single-molecule imaging of quantum interference.
abstract: The observation of interference patterns in double-slit experiments with massive particles is generally regarded as the ultimate demonstration of the quantum nature of these objects. Such matter-wave interference has been observed for electrons, neutrons, atoms and molecules and, in contrast to classical physics, quantum interference can be observed when single particles arrive at the detector one by one. The build-up of such patterns in experiments with electrons has been described as the "most beautiful experiment in physics". Here, we show how a combination of nanofabrication and nano-imaging allows us to record the full two-dimensional build-up of quantum interference patterns in real time for phthalocyanine molecules and for derivatives of phthalocyanine molecules, which have masses of 514 AMU and 1,298 AMU respectively. A laser-controlled micro-evaporation source was used to produce a beam of molecules with the required intensity and coherence, and the gratings were machined in 10-nm-thick silicon nitride membranes to reduce the effect of van der Waals forces. Wide-field fluorescence microscopy detected the position of each molecule with an accuracy of 10 nm and revealed the build-up of a deterministic ensemble interference pattern from single molecules that arrived stochastically at the detector. In addition to providing this particularly clear demonstration of wave-particle duality, our approach could also be used to study larger molecules and explore the boundary between quantum and classical physics.
authors.affiliation: Vienna Center of Quantum Science and Technology, Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090                 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Juffmann
authors.forename: Adriana
authors.initials: A
authors.lastname: Milic
authors.forename: Michael
authors.initials: M
authors.lastname: Müllneritsch
authors.forename: Peter
authors.initials: P
authors.lastname: Asenbaum
authors.forename: Alexander
authors.initials: A
authors.lastname: Tsukernik
authors.forename: Jens
authors.initials: J
authors.lastname: Tüxen
authors.forename: Marcel
authors.initials: M
authors.lastname: Mayor
authors.forename: Ori
authors.initials: O
authors.lastname: Cheshnovsky
authors.forename: Markus
authors.initials: M
authors.lastname: Arndt
mesh_terms: D003198:Computer Simulation; D004867:Equipment Design; D007211:Indoles / Q000737:chemistry; D054833:Isoindoles; D057054:Molecular Imaging / Q000295:instrumentation / Q000379:methods*; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D011789:Quantum Theory; D059629:Signal-To-Noise Ratio
chemical_list: D007211:Indoles; D054833:Isoindoles; C013647:phthalocyanine