In matter wave interferometry, detectors detect individual particles; the wave picture (interference pattern) emerges only as a statistical aggregation, after a large number of particles have been detected. Feynman, mystified by such facts, declared that 'nobody understands quantum mechanics'. A few decades later, Ketterle summed up the situation as 'one gets used to preparing waves and detecting particles'. But why are matter waves detected only as particles? Is there a law of nature forbidding their detection as waves? This question does not seem to have been addressed. The present communication suggests that it may be possible to detect matter waves as waves if there exists a nonlocal interaction - due to wave-particle duality - that causes a nonlocal transfer of energy and momentum from microscopic objects to mesoscopic or macroscopic ones. It describes the principle of a possible wave detector and the scheme of an experiment. The experiment may be feasible in the foreseeable future with a mesoscopic detector made of carbon nanostructures, or in an earth satellite in an elliptical orbit. The detection of a single atom or molecule as a wave will have enormous consequences, both practical and conceptual.
In matter wave interferometry, detectors detect individual particles; the wave picture (interference pattern) emerges only as a statistical aggregation, after a large number of particles have been detected. Feynman, mystified by such facts, declared that 'nobody understands quantum mechanics'. A few decades later, Ketterle summed up the situation as 'one gets used to preparing waves and detecting particles'. But why are matter waves detected only as particles? Is there a law of nature forbidding their detection as waves? This question does not seem to have been addressed. The present communication suggests that it may be possible to detect matter waves as waves if there exists a nonlocal interaction - due to wave-particle duality - that causes a nonlocal transfer of energy and momentum from microscopic objects to mesoscopic or macroscopic ones. It describes the principle of a possible wave detector and the scheme of an experiment. The experiment may be feasible in the foreseeable future with a mesoscopic detector made of carbon nanostructures, or in an earth satellite in an elliptical orbit. The detection of a single atom or molecule as a wave will have enormous consequences, both practical and conceptual.
Feynman contended that the double-slit experiment contained the `only mystery' in quantum mechanics. The mystery was that electrons traverse the interferometer as waves, but are detected as particles. This note was motivated by the question whether single electrons can be detected as waves. It suggests a double-slit interferometry experiment with atoms of noble gases in which it may be possible to detect an individual atom as a probability wave, using a detector which can execute two different types of simple harmonic motion: as a simple pendulum, and as a torsion pendulum. In the experiment, a torsional oscillation will never be induced by the impact of a probability wave, but will always be induced by the impact of a particle. Detection as a wave is contingent on the atom interacting much more strongly with the macroscopic detector as a whole than with its microscopic constituents. This requirement may be more difficult to meet with electrons, protons, neutrons or photons than with atoms.
Here, the concept of a wave-particle duality is questioned. First, the experimental proofs existing, respectively, for particles and waves are examined. In the case of particles, no experimental evidence can be found which establishes them; it seems that particles have always been taken for granted. In the case of waves, considerable evidence has accumulated with results on diffraction, interference, and self-interference of larger and larger objects. Then an important remark is made concerning the fact that unlike particles, waves are not observation-dependent: waves existed before observation otherwise the patterns of diffraction or interference would not have been appearing; the wave nature does not depend on the making of a measurement, there is no measurement problem for waves. Consequently, since waves are not observation-dependent, if the objects are demonstrated to be waves, they are only waves. This fact, along with some other evidence, disagrees with the current interpretation of the Wheeler-type delayed-choice experiments, where the absence of interference is interpreted as a particle behavior. Finally, recent works regarding the de Broglie‐Bohm theory are presented, which lead to suggest a new wave-only version of this theory. It is concluded that a wave-only view might be worth considering instead of the wave-particle duality view which has prevailed so far.
One of the cornerstones of quantum physics is the wave nature of matter. It explains experimentally observed effects like interference and diffraction, occurring when an object moves from one place to another along several indistinguishable ways simultaneously. The wave nature disappears when the individual ways are distinguishable. In this case, the particle nature of the object becomes visible. To determine the particle nature quantitatively, the way of the object has to be measured. Here, large progress has been made recently with new techniques, enabling one to investigate single moving atoms in a controlled manner. Two examples are discussed in the following two sections. The first experiment describes an atom interferometer, where the way of the atom is entangled with its internal state. This allows one to explore the origin of wave-particle duality and perform a quantitative test of this fundamental principle. The second experiment reports on the observation of an atom-photon molecule, a bound state between an atom and a single photon. A fascinating aspect of this system is that it makes possible to monitor the motion of a single neutral atom in real time.
1.1 Waves and particles in quantum mechanics In spite of the fact that the extraordinary progress of experimental techniques make us able to manipulate at will systems made of any small and well defined number of atoms, electrons and photons making therefore possible the actual performance of the gedankenexperimente that Einstein and Bohr had imagined to support their opposite views on the physical properties of the wavelike/particlelike objects (quantons) of the quantum world it does not seem that, after more than eighty years, a unanimous consensus has been reached in the physicist's community on how to understand their strange properties. Unfortunately, we cannot know whether Feynman would still insist in maintaining his famous sentence It is fair to say that nobody understands quantum mechanics. We can only discuss if, almost thirty years after his death, some progress towards this goal has been made. I believe that this is the case. I will show in fact that, by following the suggestions of Feynman himself, some clarification of the old puzzles can be achieved. This chapter therefore by no means is intended to provide an impartial review of the present status of the question but is focused on the exposure of the results of more than twenty years of research of my group in Rome, which in my opinion provide a possible way of connecting together at the same time the random nature of the events at the atomic level of reality and the completeness of their probabilistic representation by the principles of Quantum Mechanics.
Abstract One of the cornerstones of quantum physics is the wave nature of matter. It explains experimentally observed effects like interference and diffraction, occurring when an object moves from one place to another along several indistinguishable ways simultaneously. The wave nature disappears when the individual ways are distinguishable. In this case, the particle nature of the object becomes visible. To determine the particle nature quantitatively, the way of the object has to be measured. Here, large progress has been made recently with new techniques, enabling one to investigate single moving atoms in a controlled manner. Two examples are discussed in the following two sections. The first experiment describes an atom interferometer, where the way of the atom is entangled with its internal state. This allows one to explore the origin of wave‐particle duality and perform a quantitative test of this fundamental principle. The second experiment reports on the observation of an atom‐photon molecule, a bound state between an atom and a single photon. A fascinating aspect of this system is that it makes possible to monitor the motion of a single neutral atom in real time.
Abstract The double-slit experiment is a classic experiment that presents the clearest manifestation of wave-particle duality, one of the fundamental principles of quantum mechanics. The double-slit experiment still remains the phenomenon that demonstrates wave-particle duality at the most fundamental level. This phenomenon quantitatively and conceptually demonstrates that microscopic objects can behave like both waves and particles at the same time. This article provides an in-depth analysis of the physical nature of dualism, the mechanism of formation of the interference pattern, and the impact of the act of observation on the dynamics of quantum systems. The need for a new perspective on this topic is due to the fact that the current uncertainty in the interpretation of quantum reality has not yet been completely eliminated, and the boundaries between classical and quantum behavior in microscopic objects are still being explored. The results presented here restructure the deep mechanisms of the interference picture, more clearly frame the relationship between observation and wavefunction collapse, and provide a quantum. Since the article attempts to provide a complete answer to the mechanism of the formation of wave-particle duality, extensive space is given to sections such as historical development, theoretical models, modern research, etc. New approaches to this phenomenon have been developed using modern research and string theory. As a result, a new mathematical expression has been proposed that explains the reasons for the initial emergence of wave-particle duality, and is also important for string theory. The article explains the measurement problem with a more effective physical structure and ontological model.