The quantum superposition principle, which expresses the idea that a system can exist simultaneously in two or more mutually exclusive states is at the heart of the mystery of quantum mechanics. This paper presents an axiom, called the principle of actualizable histories, which naturally leads to the quantum superposition principle. However, in order to be applicable to massive systems, it requires introducing a novel distinction between actualizable and actual mass. By means of arriving in conjunction with two previously introduced axioms at the path integral formulation of quantum mechanics, it is shown that actualizable mass is the central concept of mass in quantum theory, whereas actual mass is the central concept in classical theories, and in particular general relativity. This distinction sharply segregates the domains of validity of the two theories, making it incompatible with any theory of quantum gravity which does not respect this segregation. Finally, an experiment is suggested to test this idea.
The quantum superposition principle, which expresses the idea that a system can exist simultaneously in two or more mutually exclusive states is at the heart of the mystery of quantum mechanics. This paper presents an axiom, called the principle of actualizable histories, which naturally leads to the quantum superposition principle. However, in order to be applicable to massive systems, it requires introducing a novel distinction between actualizable and actual mass. By means of arriving in conjunction with two previously introduced axioms at the path integral formulation of quantum mechanics, it is shown that actualizable mass is the central concept of mass in quantum theory, whereas actual mass is the central concept in classical theories, and in particular general relativity. This distinction sharply segregates the domains of validity of the two theories, making it incompatible with any theory of quantum gravity which does not respect this segregation. Finally, an experiment is suggested to test this idea.
Ever since quantum mechanics was first developed, it has been unclear what it really tells us about reality. A novel framework, based on 5 axioms, is presented here which offers an interpretation of quantum mechanics unlike any considered thus far: It is postulated that physical objects can exist in one of two distinct modes, based on whether they have an intrinsic actual spacetime history or not. If they do, their mode of existence is actual and they can be described by classical physics. If they do not, then their mode of existence is called actualizable and they must be described in terms of an equal-weight superposition of all possible actualizable (not actual) histories. The distinction is based on an axiom according to which there exists a limit in which spacetime reduces to a one-dimension reduced version, called areatime, and that objects which merely actualizably exist in spacetime actually exist in areatime. The operational comparison of the passage of time for such objects to the passage of time for a spacetime observer is postulated to be made possible by what is called an angular dual bilateral symmetry. This symmetry can be decomposed into the superposition of two imaginary phase angles of opposite sign. To mathematically describe the spacetime manifestation of objects which actually exist in areatime, each actualizable spacetime history is associated with an actualizable path, which in turn is associated with the imaginary phases. For a single free particle, the complex exponent is identified with a term proportional to its relativistic action, thus recovering the path integral formulation of quantum mechanics. Although based on some highly unfamiliar ideas, this framework appears to render at least some of the usual mysteries connected with quantum mechanics amenable to simple conceptual understanding. It also appears to connect the foundations of quantum theory to the foundation of the special theory of relativity while clarifying its relationship to the general theory of relativity and yields a testable prediction about a type of experiment, as yet unperformed, which under the current paradigm is utterly unexpected, namely, that the gravitational field of radiation is zero. The paper concludes with some speculations about how the theory may be extended to a metatheory of nature.(Note the paper was edited on 3-October-2011 to remove one sentence on page 7)
Abstract Despite almost a century’s worth of study, it is still unclear how general relativity (GR) and quantum theory (QT) should be unified into a consistent theory. The conventional approach is to retain the foundational principles of QT, such as the superposition principle, and modify GR. This is referred to as ‘quantizing gravity’, resulting in a theory of ‘quantum gravity’. The opposite approach is ‘gravitizing QT’ where we attempt to keep the principles of GR, such as the equivalence principle, and consider how this leads to modifications of QT. What we are most lacking in understanding which route to take, if either, is experimental guidance. Here we consider using a Bose–Einstein condensate (BEC) to search for clues. In particular, we study how a single BEC in a superposition of two locations could test a gravitizing QT proposal where wavefunction collapse emerges from a unified theory as an objective process, resolving the measurement problem of QT. Such a modification to QT due to general relativistic principles is testable near the Planck mass scale, which is much closer to experiments than the Planck length scale where quantum, general relativistic effects are traditionally anticipated in quantum gravity theories. Furthermore, experimental tests of this proposal should be simpler to perform than recently suggested experiments that would test the quantizing gravity approach in the Newtonian gravity limit by searching for entanglement between two massive systems that are both in a superposition of two locations.
Ever since quantum mechanics was first developed, it has been unclear what it really tells us about reality. A novel framework, based on 5 axioms, is presented here which offers an interpretation of quantum mechanics unlike any considered thus far: It is postulated that physical objects can exist in one of two distinct modes, based on whether they have an intrinsic actual spacetime history or not. If they do, their mode of existence is actual and they can be described by classical physics. If they do not, then their mode of existence is called actualizable and they must be described in terms of an equal-weight superposition of all possible actualizable (not actual) histories. The distinction is based on an axiom according to which there exists a limit in which spacetime reduces to a one-dimension reduced version, called areatime, and that objects which merely actualizably exist in spacetime actually exist in areatime. The operational comparison of the passage of time for such objects to the passage of time for a spacetime observer is postulated to be made possible by what is called an angular dual bilateral symmetry. This symmetry can be decomposed into the superposition of two imaginary phase angles of opposite sign. To mathematically describe the spacetime manifestation of objects which actually exist in areatime, each actualizable spacetime history is associated with an
This paper argues that the case for “gravitizing” quantum theory is at least as strong as that for quantizing gravity. Accordingly, the principles of general relativity must influence, and actually change , the very formalism of quantum mechanics. Most particularly, an “Einsteinian”, rather than a “Newtonian” treatment of the gravitational field should be adopted, in a quantum system, in order that the principle of equivalence be fully respected. This leads to an expectation that quantum superpositions of states involving a significant mass displacement should have a finite lifetime, in accordance with a proposal previously put forward by Diósi and the author.
Textbook quantum superposition refers to the feature that certain linear combinations of Hilbert space rays, each representing a valid quantum state, are themselves valid states. This notion is not operational, and it relies on the underlying Hilbert space formalism. Recent proposals for experimental tests of indefinite causal order, as well as tests probing the non-classicality of gravity, pivot on superposition, thereby calling for a theory-independent, operational formalisation of the concept. Here, we define superposition within the framework of Generalised Probabilistic Theories, based on observed statistics in prepare-and-measure experiments. Using this, we formulate three superposition principles to investigate which structural features of quantum theory carry over to other theories. We study conditions under which these principles carry over from subsystems to their compositions; to this end, we show that the quantum tensor product emerges as the largest composition rule for quantum systems respecting all three principles. Furthermore, we show how non-classical features such as entanglement and preparational uncertainty can be viewed as special forms of superposition.
One of the most profound and difficult problems of physics in the last century is the construction of a simple theory which unites the ideas of quantum mechanics and relativity. The concepts which are used in quantum mechanics related to the measurements of positions, momenta, energy and time, are the same concepts in terms of which the special relativistic postulates are formulated. Hence, it is at least possible to formulate the requirement of special relativistic invariance for quantum theories and to ascertain whether these requirements are satisfied. The fact that the answer is nearer to no than to yes, that quantum mechanics has not yet been fully adjusted to the postulates of the special theory, is perhaps irritating. In the general theory of relativity, the situation is different: the space-time coordinates are only auxiliary quantities to which arbitrary values for every event could be given. Hence, the measurement of position, that is, of the space coordin ates, is certainly not a significant measurement if the postulates of the general theory are adopted: any arbitrary value can be given to the coordinates. The same holds for momenta. The purpose of this brief paper is to make in principle some personal and particular remarks on the fundamental concepts of time and mass. Some comments about the consequences on the relativistic dynamics of quantum systems are also formulated.