Summary form only given, as follows. In a recent experiment we were able to demonstrate the de Broglie wave character of the fullerene molecule C/sub 60/ by diffraction at a free standing material grating. This proves that it is possible to preserve quantum coherence almost completely in the external degrees of freedom of a hot, massive and complex object over a long time and distance. This may seem astonishing in the light of the fact that the fullerenes were produced in a thermal source which was kept at about 900 K. At such a high temperature the de Broglie wavelength is about 400 times smaller than the size of the molecule (/spl lambda//sub dB//spl sim/25 pm), all internal degrees of freedom (174 different vibrational modes, and rotational modes up to J>100) are excited and the molecules may emit a few infrared photons (blackbody radiation and vibrational quanta) during their time of flight through the apparatus. Our published measurements so far have been essentially consistent with the absence of decoherence during the time of flight of the molecules. The interference contrast in all experiments has however so far been limited by the thermal velocity spread and the finite collimation of the fullerene beam.
Summary form only given, as follows. In a recent experiment we were able to demonstrate the de Broglie wave character of the fullerene molecule C/sub 60/ by diffraction at a free standing material grating. This proves that it is possible to preserve quantum coherence almost completely in the external degrees of freedom of a hot, massive and complex object over a long time and distance. This may seem astonishing in the light of the fact that the fullerenes were produced in a thermal source which was kept at about 900 K. At such a high temperature the de Broglie wavelength is about 400 times smaller than the size of the molecule (/spl lambda//sub dB//spl sim/25 pm), all internal degrees of freedom (174 different vibrational modes, and rotational modes up to J>100) are excited and the molecules may emit a few infrared photons (blackbody radiation and vibrational quanta) during their time of flight through the apparatus. Our published measurements so far have been essentially consistent with the absence of decoherence during the time of flight of the molecules. The interference contrast in all experiments has however so far been limited by the thermal velocity spread and the finite collimation of the fullerene beam.
The 1999 experiment reported by Markus Arndt, Olaf Nairz, Julian Vos-Andreae, Claudia Keller, Gerbrand van der Zouw, and Anton Zeilinger in Nature demonstrated de Broglie matter-wave interference for C60 fullerene molecules, extending experimen- tally observable quantum coherence to an object of unprecedented mass and internal complexity at the time (Arndt et al. 1999). This article develops a complete critical– propositional analysis of that experiment in systematic dialogue with the Theory of Objectivity (TO), as developed by Vidamor Cabannas and Denivaldo Silva. The analysis distinguishes three epistemological levels that must not be conflated: the experimentally established phenomenon of molecular interference; the physical interpretation supplied by quantum mechanics and decoherence theory; and the modal- ontological claims of the TO. This distinction is essential because empirical compatibility with a modal ontology is not equivalent to demonstration of modal necessity. The C60 experiment is especially relevant to the TO in four domains. First, a complex composed object behaves as a coherent quantum unit at the level of its center- of-mass propagation, providing a meaningful point of dialogue with the compositional structure associated with Absolute Truth 6 (VA6). Second, the diffraction grating is not merely a passive geometrical boundary: molecule–surface interactions modify the effective slit width, generating an empirically measurable interface between geometry and dynamics and providing a strong operational bridge to Absolute Truth 4 (VA4). Third, the preservation or destruction of interference depends on correlations between the molecule and its environment, thereby connecting physical distinguishability, infor- mation, and radiation. This creates the most significant point of contact with Absolute Truth 7 (VA7), under which the TO identifies its transcendent element with knowledge or information produced in atomic relations and regards such information as equivalent to atomic radiation. Fourth, the experiment offers possible operational analogues for the TO’s Inducing Effects, although these analogues must not be treated as established identities without independent derivation. The article also examines possible relations to VA1–VA7, the TO phenomenic elements, the Cosmogonic Theorem, and the cosmological Eras. It argues that the C60 experiment provides selective and indirect empirical corroboration for operational projections compatible with VA4, VA6, and VA7, but does not constitute confirmation of the TO as a complete ontology. Later experiments on thermal decoherence strengthen the radiation–information bridge by showing that photon emission can reduce molecular interference when it becomes capable of encoding spatial information (Hackermüller et al. 2004). In dialogue with Heisenberg, Einstein, Bohm, Joos and Zeh, Zurek, Aspect, Planck, LIGO/Virgo, JWST observations, and Petina’s taxonomy of fundamental laws, the paper proposes a research program capable of converting qualitative TO correspondences into quantitative and potentially discriminatory predictions. The central methodological conclusion is that the scientific strength of the TO will not depend on retrospectively redescribing established quantum phenomena in its own vocabulary, but on deriving from its modal architecture measurable relations that either reproduce quantum theory from more fundamental principles or predict deviations in controlled regimes. Keywords: Theory of Objectivity; C60; fullerene; matter waves; wave–particle duality; quantum interference; decoherence; information; boundaries; radiation; modal ontology; empirical corroboration.
We study C70 fullerene matter waves in a Talbot-Lau interferometer as a function of their temperature. While the ideal fringe visibility is observed at moderate molecular temperatures, we find a gradual degradation of the interference contrast if the molecules are heated before entering the interferometer. A method is developed to assess the distribution of the microcanonical temperatures of the molecules in free flight. This way the heating-dependent reduction of interference contrast can be compared with the predictions of quantum theory. We find that the observed loss of coherence agrees quantitatively with the expected decoherence rate due to the thermal radiation emitted by the hot molecules.
The wave nature of matter is a key ingredient of quantum physics and yet it defies our classical intuition. First proposed by Louis de Broglie a century ago, it has since been confirmed with a variety of particles from electrons up to molecules. Here we demonstrate new high-contrast quantum experiments with large and massive tailor-made organic molecules in a near-field interferometer. Our experiments prove the quantum wave nature and delocalization of compounds composed of up to 430 atoms, with a maximal size of up to 60 Å, masses up to m=6,910 AMU and de Broglie wavelengths down to λdB=h/mv≃1 pm. We show that even complex systems, with more than 1,000 internal degrees of freedom, can be prepared in quantum states that are sufficiently well isolated from their environment to avoid decoherence and to show almost perfect coherence. Observing superposition states of mesoscopic quantum systems is an ongoing challenge. Gerlichet al. report quantum interference of large tailor-made organic compounds, demonstrating delocalization and the quantum wave nature of entire molecules composed of up to 430 atoms.
We discuss new de Broglie coherence experiments in a near-field molecule interferometer with a variety of large organic molecules. While de Broglie coherence is to first order only associated with the center-of-mass motion of the diffracted particle, we here investigate the question as to which extent the internal molecular property is relevant for, compatible with or detrimental for maintaining coherence in the translational degree of freedom. External perturbations, such as inhomogeneous external electric fields, may influence the delocalized molecules inside the matter wave interferometer and they allow us to access the molecular polarizabilities, permanent or even fluctuating electric dipole moments. We extract information about the molecular states from the interference phase shifts as well as from the observed dephasing in a Kapitza-Dirac Talbot-Lau-Stark-deflectometer. We discuss the relevance of our experiments with regard to both molecule metrology and the foundations of quantum mechanics, i.e. the preservation of coherence for highly complex particles in external fields.
We provide a self-contained quantum description of the interference produced by macromolecules diffracted by a grating, with particular reference to fullerene interferometry experiments. We analyze the processes inducing loss of coherence consisting in beam preparation (collimation setup and thermal spread of the wavelengths of the macromolecules) and in environmental disturbances. The results show a good agreement with experimental data and highlight the analogy with optics. Our analysis gives some hints for planning future experiments.
Wave–particle duality is frequently the first topic students encounter in elementary quantum physics. Although this phenomenon has been demonstrated with photons, electrons, neutrons, and atoms, the dual quantum character of the famous double-slit experiment can be best explained with the largest and most classical objects, which are currently the fullerene molecules. The soccer-ball-shaped carbon cages C60 are large, massive, and appealing objects for which it is clear that they must behave like particles under ordinary circumstances. We present the results of a multislit diffraction experiment with such objects to demonstrate their wave nature. The experiment serves as the basis for a discussion of several quantum concepts such as coherence, randomness, complementarity, and wave–particle duality. In particular, the effect of longitudinal (spectral) coherence can be demonstrated by a direct comparison of interferograms obtained with a thermal beam and a velocity selected beam in close analogy to the usual two-slit experiments using light.