In the standard quantum theory at both the particle and field level, there is the important theoretical and conceptual background of the classical spacetime. We develop a novel approach to put the quantum structure into spacetime itself, or rather its quantum counterpart. The starting point here is to incorporate the qauntum ħ into the (special) relativity for the ‘quantum spacetime’. We will introduce the novel framework and its most recent development.
In the standard quantum theory at both the particle and field level, there is the important theoretical and conceptual background of the classical spacetime. We develop a novel approach to put the quantum structure into spacetime itself, or rather its quantum counterpart. The starting point here is to incorporate the qauntum ħ into the (special) relativity for the ‘quantum spacetime’. We will introduce the novel framework and its most recent development.
Up to this point, our study of quantum mechanics has concerned itself with the behaviour of particles that inhabit a Galilean spacetime. For many purposes, in atomic, molecular and condensed matter physics, this theory is quite adequate. We saw in earlier chapters, however, that our actual spacetime has a structure which is much closer to that of the Minkowski spacetime of special relativity and that more general structures must be considered when gravitational phenomena are signicant. From a purely theoretical point of view, it is therefore important to formulate quantum theory in a way which is consistent with these more general spacetimes. The benets of constructing a relativistic quantum theory actually go far beyond the aesthetic satisfaction of making our geometrical and quantum-mechanical reasoning compatible. For one thing, we shall discover that the relativistic theory provides a deeper understanding of spin and the distinction between fermions and bosons, which in the non-relativistic theory appear simply as facts of life that we must strive to accommodate. Also, of course, there are many situations in which relativistic eects become observable, for which non-relativistic theory provides no explanation. The most obvious are high-energy scattering experiments, in which particles acquire kinetic energies comparable with or greater than their rest energies mc2, and the correct 4-momentum (3.33) must be used. There are, however, more subtle eects, such as the spin-orbit coupling that is essential for interpreting atomic spectra, which are also of relativistic origin.
Up to this point, our study of quantum mechanics has concerned itself with the behaviour of particles that inhabit a Galilean spacetime. For many purposes, in atomic, molecular and condensed matter physics, this theory is quite adequate. We saw in earlier chapters, however, that our actual spacetime has a structure which is much closer to that of the Minkowski spacetime of special relativity and that more general structures must be considered when gravitational phenomena are significant. From a purely theoretical point of view, it is therefore important to formulate quantum theory in a way which is consistent with these more general spacetimes. The benefits of constructing a relativistic quantum theory actually go far beyond the aesthetic satisfaction of making our geometrical and quantummechanical reasoning compatible. For one thing, we shall discover that the relativistic theory provides a deeper understanding of spin and the distinction between fermions and bosons, which in the non-relativistic theory appear simply as facts of life that we must strive to accommodate. Also, of course, there are many situations in which relativistic effects become observable, for which nonrelativistic theory provides no explanation. The most obvious are high-energy scattering experiments, in which particles acquire kinetic energies comparable with or greater than their rest energies mc2, and the correct 4-momentum (3.34) must be used. There are, however, more subtle effects, such as the spin-orbit coupling that is essential for interpreting atomic spectra, which are also of relativistic origin.
Student research work in high school on the fundamental principles of quantum mechanics.Abstract:Quantum physics represents one of the most profound conceptual revolutions in modern science,redefining the foundations of matter, energy, and spacetime. This paper presents a structuredtheoretical examination of the development and implications of quantum mechanics, beginningwith the resolution of the ultraviolet catastrophe through energy quantization and extending tothe emergence of wave–particle duality, superposition, and intrinsic indeterminacy. By tracingthe contributions of Planck, Einstein, de Broglie, Schrödinger, Heisenberg, and Dirac, the workanalyzes the transition from classical determinism to probabilistic wave mechanics and thesubsequent formulation of quantum electrodynamics (QED) and quantum field theory (QFT).Particular attention is given to the conceptual shift from particles as localized objects toexcitations of underlying fields, providing a framework for understanding particle interactions,conservation laws, and the Standard Model of particle physics. The tension between quantummechanics and general relativity is examined through the unresolved problem of quantumgravity, highlighting the theoretical limitations that persist at singularities and Planck-scaleregimes. Rather than treating classical and quantum theories as irreconcilable domains, this studyconsiders their structural interplay and philosophical implications, emphasizing the need for aunified framework that coherently incorporates spacetime and quantization. The analysisprovides a qualitative synthesis intended to support future quantitative investigations intofundamental physics and the continued development of quantum technologies.
The dissertation investigates some relevant metaphysical issues arising in the context of spacetime theories. In particular, the inquiry focuses on general relativity and canonical quantum gravity. A formal definition of spacetime theory is proposed and, against this framework, an analysis of the notions of general covariance, symmetry and background independence is performed. It is argued that many conceptual issues in general relativity and canonical quantum gravity derive from putting excessive emphasis on general covariance as an ontological prin-ciple. An original metaphysical position grounded in scientific essential- ism and causal realism (weak essentialism) is developed and defended. It is argued that, in the context of general relativity, weak essentialism supports spacetime substantivalism. It is also shown that weak essentialism escapes arguments from metaphysical underdetermination by positing a particular kind of causation, dubbed geometric. The proposed interpretive framework is then applied to Bohmian mechanics, pointing out that weak essentialism nicely fits into this theory. In the end, a possible Bohmian implementation of loop quantum gravity is considered, and such a Bohmian approach is interpreted in a geometric causal fashion. Under this interpretation, Bohmian loop quantum gravity straightforwardly commits us to an ontology of elementary extensions of space whose evolution is described by a non-local law. The causal mechanism underlying this evolution clarifies many conceptual issues related to the emergence of classical spacetime from the quantum regime. Although there is as yet no fully worked out physical theory of quantum gravity, it is argued that the proposed approach sets up a standard that proposals for a serious ontology in this field should meet.
We revisit quantum field theory in curved spacetime (QFTCS) as a semi-classical framework for quantum matter on classical geometries, emphasizing its limitations, including vacuum ambiguity and background dependence. We briefly review major approaches to quantum gravity (QG), including Loop Quantum Gravity (LQG), string theory, and asymptotic safety, highlighting their conceptual challenges. Motivated by these issues, we outline a teleparallel framework based on coframe and spin-connection variables, where gravity is encoded in torsion rather than curvature. This framework naturally incorporates local Lorentz symmetry and fermionic couplings while displaying a gauge-like structure. We argue that the coframe/spin-connection pair provides an alternative and geometrically refined description of gravitational variables, which may serve as a useful starting point for future investigations of QG. The purpose of this work is not to provide a complete quantization of teleparallel gravity but to identify the geometric and conceptual ingredients that such a formulation would require.