We believe that physics education has to meet today’s requirement for a qualitative approach to Quantum Mechanics (QM) worldview. An effective answer to the corresponding instructional problem might allow the basic ideas of QM to be accessed atan early stage of physics education. This paper presents part of a project that aims at introducing a sufficient, simple, and relevant teaching approach towards QM into in-/preservice teacher education, i.e., at providing teachers with the indispensable scientific knowledge and epistemological base needed for (...) a reform of science education along the aforementioned line. The investigation of teacher–learners’ (t-ls’) initial knowledge indicated that their main misconceptions appear to be the result of their pre-/in university traditional instruction, which causes the overlapping/mix-up of the conceptual frameworks of Classical Physics (CP) and QM. Assuming that these misconceptions form by nature epistemological obstacles to the acquisition of QM knowledge, the educational strategy proposed here aims at leading t-ls to form a conceptual structure that includes CP and QM as two totally independent conceptual systems. Accepting, furthermore, that the complete distinction of these systems demands a radical reconstruction of t-ls’ initial knowledge, we present here an instructional model that bases the required reconstruction on the juxtaposition of two models that constitute the signal point of twentieth century’s “paradigm shift”: (a) Bohr’s semiclassical atom model, and (b) the model of the atom accepted by modern physics theory. (shrink)

Quantum mechanics is a very successful theory that has impacted on many areas of physics, from pure theory to applications. However, it is difficult to interpret, and philosophical contradictions and counterintuitive results are apparent at a fundamental level. In this book, Laloë presents our current understanding of the theory. The book explores the basic questions and difficulties that arise with the theory of quantum mechanics. It examines the various interpretations that have been proposed, describing and comparing them and discussing their (...) success and difficulties. The book is ideal for researchers in physics and mathematics who want to know more about the problems faced in quantum mechanics but who do not have specialist knowledge in the subject. It will also interest philosophers of science specializing in quantum physics. (shrink)

THE PRINCIPLE OF SUPERPOSITION. The need for a quantum theory Classical mechanics has been developed continuously from the time of Newton and applied to an ...

A scientific community cannot practice its trade without some set of received beliefs. These beliefs form the foundation of the "educational initiation that prepares and licenses the student for professional practice". The nature of the "rigorous and rigid" preparation helps ensure that the received beliefs are firmly fixed in the student's mind. Scientists take great pains to defend the assumption that scientists know what the world is like...To this end, "normal science" will often suppress novelties which undermine its foundations. Research (...) is therefore not about discovering the unknown, but rather "a strenuous and devoted attempt to force nature into the conceptual boxes supplied by professional education". (shrink)

Thomas S. Kuhn's classic book is now available with a new index.

The periodic table of the elements is one of the most powerful icons in science: a single document that captures the essence of chemistry in an elegant pattern. Indeed, nothing quite like it exists in biology or physics, or any other branch of science, for that matter. One sees periodic tables everywhere: in industrial labs, workshops, academic labs, and of course, lecture halls. It is sometimes said that chemistry has no deep ideas, unlike physics, which can boast quantum mechanics and (...) relativity, and biology, which has produced the theory of evolution. This view is mistaken, however, since there are in fact two big ideas in chemistry. They are chemical periodicity and chemical bonding, and they are deeply interconnected. The observation that certain elements prefer to combine with specific kinds of elements prompted early chemists to classify the elements in tables of chemical affinity. Later these tables would lead, somewhat indirectly, to the discovery of the periodic system, perhaps the biggest idea in the whole of chemistry. Indeed, periodic tables arose partly through the attempts by Dimitri Mendeleev and numerous others to make sense of the way in which particular elements enter into chemical bonding. (shrink)

Sir Karl Popper is one of the few authors to have discussed the reduction of chemistry. His approach consists of what I term naturalistic reduction, which I suggest bears close similarities to the way in which scientists regard reduction. The present article aims to build on Popper's insights into the nature of reduction in science and more specifically to suggest an approach to characterizing a specific sense of the notion of approximate reduction in the context of chemistry. In the course (...) of the discussion, one of Popper's better known passages on the reduction of chemistry is analysed in some detail. (shrink)

We discuss the main results of Linear Stochastic Electrodynamics, starting from a reformulation of its basic assumptions. This theory shares with Stochastic Electrodynamics the core assumption that quantization comes about from the permanent interaction between matter and the vacuum radiation field, but it departs from it when it comes to considering the effect that this interaction has on the statistical properties of the nearby field. In the transition to the quantum regime, correlations between field modes of well-defined characteristic frequencies arise, (...) which coincide with the transition frequencies of quantum mechanics and are therefore directly related with the energy quantization. The Heisenberg equations of motion of (non-relativistic) quantum electrodynamics are thus obtained. After a detailed consideration of the significance of the approximations made, we present a discussion on some of the most delicate or controversial features of quantum mechanics from the perspective provided by the present theory. (shrink)

In the May 15, 1935 issue of Physical Review Albert Einstein co-authored a paper with his two postdoctoral research associates at the Institute for Advanced Study, Boris Podolsky and Nathan Rosen. The article was entitled “Can Quantum Mechanical Description of Physical Reality Be Considered Complete?” (Einstein et al. 1935). Generally referred to as “EPR”, this paper quickly became a centerpiece in the debate over the interpretation of the quantum theory, a debate that continues today. The paper features a striking case (...) where two quantum systems interact in such a way as to link both their spatial coordinates in a certain direction and also their linear momenta (in the same direction). As a result of this “entanglement”, determining either position or momentum for one system would fix (respectively) the position or the momentum of the other. EPR use this case to argue that one cannot maintain both an intuitive condition of local action and the completeness of the quantum description by means of the wave function. This entry describes the argument of that 1935 paper, considers several different versions and reactions, and explores the ongoing significance of the issues they raise. (shrink)

The article disputes the recent claim featured in "Nature" magazine and many other science magazines to the effect that atomic orbitals have been observed for the first time. The claim is incorrect in view of the unconvincing nature of the evidence adduced and since atomic orbitals are deemed unobservable in principle by quantum mechanics. In addition, the possible educational drawbacks of this incorrect claim are discussed.

First-ever comprehensive introduction to the major new subject of quantum computing and quantum information.

The historical development of the electronic configuration model is traced and the status of the model with respect to quantum mechanics is examined. The successes and problems raised by the model are explored, particularly in chemical ab initio calculations. The relevance of these issues to whether chemistry has been reduced to quantum mechanics is discussed, as are some general notions on reduction.

Molecular structure (MS) has been treated as a convention or an epiphenomenon by physicists and quantum chemists interpreting the mathematical formalism of quantum mechanics as the essential reality criterion in the submicroscopic world (R2 world). This paper argues that, (a) even in the R2 world there is a class of entities which are real per se, even though they cannot be separated from their material support, and MS may belong to that class; (b) MS actualizes a particular molecule from the (...) many potentialities of a given set of nuclei and electrons, all present in the same Schroedinger equation; (c) MS is a fact established in the XIXth century, albeit as a result of circumstantial evidence (because of its belonging to the R2 world); (d) the fact that MS is known, as all objects of the atomic world, in terms of analogies with macroscopic models, is not valid grounds for questioning its reality; (e) MS is a set of topological as well as geometrical relations. All along the discussion, observability according to Bohr, Heisenberg, Feynman is taken as the essential criterion of reality in the R2 world. On its basis, quantum mechanics is by no means in conflict with the reality of molecular structure and shape. On the other hand, the question of the minimum lifetime required for a MS proper to exist should be left open, pending a detailed analysis of measurement techniques. (shrink)

The Einstein–Podolsky–Rosen paradox (1935) is reexamined in the light of Shannon’s information theory (1984). The EPR argument did not take into account that the observer’s information was localized, like any other physical object.

For many decades, chemists regarded rigid models of molecular structure as representing structures of real molecules as their attributes. However, new experimental data required a new theoretical conceptualization. The rigid model has been replaced with a dynamic model in which molecular structure is changed under the influence of environmental conditions. The above case shows some problems connected with recognizing theoretical models as structural representations of real empirical systems. Owing to the fact that theoretical models of molecular structure obtain local interpretations (...) with a procedural character, they can be carriers of specific information about structures of real molecules. Finally, I argue that, although theoretical models can be well corroborated empirically, they cannot be treated as representations of real empirical systems but can play a very important role in experimental practice. (shrink)

I claim that the question of whether chemistry is reduced to quantum mechanics is more ambiguous and multi-faceted than generally supposed. For example, chemistry appears to be both reduced and not reduced at the same time depending on the perspective that one adopts. Similarly, I argue that some conceptual issues in quantum mechanics are ambiguous and can only be laid to rest by embracing paradox and ambiguity rather than regarding them as obstacles to be overcome. Recent work in the reduction (...) of chemistry is also reviewed, including discussions of the ontological reduction of chemistry and the question of the emergence of chemistry from physics. (shrink)