Juan Camilo Martínez

The modal-Hamiltonian interpretation belongs to the modal family of interpretations of quantum mechanics. By endowing the Hamiltonian with the role of selecting the subset of the definite-valued observables of the system, it accounts for ideal and non-ideal measurements, and also supplies a criterion to distinguish between reliable and non-reliable measurements in the non-ideal case. It can be reformulated in an explicitly invariant form, in terms of the Casimir operators of the Galilean group, and the compatibility of the MHI with the theory of decoherence has been proved. Nevertheless, perhaps its main advantage in the eyes of a scientist is given by its several applications to well-known physical situations, leading to results compatible with experimental evidence. The purpose of this paper is to add a new application to the list: the case of optical isomerism, which is a central issue for the philosophy of physics and of chemistry since it points to the core of the problem of the relationship between physics and chemistry. Here it will be shown that the MHI supplies a direct and physically natural solution to the problem, a solution that does not require putting classical assumptions in “by hand.”

When young Kant meditated upon the distinction between his right and left hands, he could not foresee that the problem of incongruent counterparts would revive in the twentieth century under a new form. In the early days of quantum chemistry, Friedrich Hund developed the so-called Hund paradox that arises from the supposed inability of quantum mechanics to account for the difference between enantiomers. In this paper, the paradox is expressed as a case of quantum measurement, stressing that decoherence does not offer a way out of the problem. The main purpose is to argue for the need to adopt a clear interpretation of quantum mechanics in order to solve the paradox. In particular, I claim that the Modal-Hamiltonian Interpretation, which conceives measurement as a breaking-symmetry process, supplies the tools required to explain the dextro-rotation or levo-rotation properties of optical isomers.

The analysis of the concept of orbital allows us to argue that—in opposition to a recent position in philosophy of science—it is impossible to defend the autonomy of the chemical reality in regard to physical reality, appealing to the idea that there is a conceptual rupture among a chemical interpretation and a quantuminterpretation of the concept. This is the case because there are not two different interpretations of the concept of orbital. On the contrary, the concept involved in structural chemistry and in quantum chemistry comes from quantum mechanics.El análisis del concepto de orbital permite argumentar—en oposición a una propuesta reciente en filosofía de la química—que no es posible defender la autonomía ontológica de la realidad química respecto de la física, sobre la base de una ruptura conceptual entre una interpretación química del concepto y otra propia de la mecánica cuántica. Esto es así porque no existen tales interpretaciones distintas del concepto de orbital, sino que, por el contrario, este concepto en química cuántica y en química estructural proviene de la mecánica cuántica.

The analysis of the concept of orbital allows us to argue that—in opposition to a recent position in philosophy of science—it is impossible to defend the autonomy of the chemical reality in regard to physical reality, appealing to the idea that there is a conceptual rupture among a chemical interpretation and a quantuminterpretation of the concept. This is the case because there are not two different interpretations of the concept of orbital. On the contrary, the concept involved in structural chemistry and in quantum chemistry comes from quantum mechanics.El análisis del concepto de orbital permite argumentar—en oposición a una propuesta reciente en filosofía de la química—que no es posible defender la autonomía ontológica de la realidad química respecto de la física, sobre la base de una ruptura conceptual entre una interpretación química del concepto y otra propia de la mecánica cuántica. Esto es así porque no existen tales interpretaciones distintas del concepto de orbital, sino que, por el contrario, este concepto en química cuántica y en química estructural proviene de la mecánica cuántica.

In the present paper we address the problem of optical isomerism embodied in the socalled “Hund’s paradox”, which points to the difficulty to account for chirality by means of quantum mechanics. In particular, we explain the answer to the problem proposed by the theory of decoherence. The purpose of this article is to challenge this answer on the basis of a conceptual analysis of the phenomenon of decoherence, that reveals the limitations of the theory of decoherence to solve the difficulties posed by optical isomerism and, in general, by quantum measurement.

In his recent Editorial Article, Jeffrey Seeman calls for the promotion of collaborative work among different disciplines, focusing on the case of the interaction between chemistry, the history of chemistry and the philosophy of chemistry. From a general viewpoint, it is difficult to disagree with this claim; moreover, the interest of scientists in the history and the philosophy of science is always welcome. However, the devil is in the details: there are several points that, we think, must be discussed more carefully with the aim of arriving at far-reaching conclusions.

Thesemanticviewofscientifictheoriesassumesthedependenceofmodelsontheories.Someauthorschal- lenge that assumption by means of the study of certain models conceived as phenomenological. On the basis of the analysis of atomic and molecular models in quantum chemistry, in this article we will argue for an independence of models from theories, which cannot be interpreted as merely historical and context relative. Those models shows a conceptual independence that is constitutive of the modeling process; such independence cannot be conceived as a result of a contingent deficiency of the theory used, deficiency that would be overcome by the future progress of science.

Although during the last decades the philosophy of chemistry has greatly extended its thematic scope, the main difficulties appear in the attempt to link the chemical description of atoms and molecules and the description supplied by quantum mechanics. The aim of this paper is to analyze how the difficulties that threaten the continuous conceptual link between molecular chemistry and quantum mechanics can be overcome or, at least, moderated from the perspective of BM. With this purpose, in “The quantum-mechanical challenges” section the foundational incompatibility between chemical and SQM descriptions will be briefly recalled. “Bohmian mechanics” section will be devoted to explain the main features of BM. In “Empirical equivalence and underdetermination” section, the consequences of the empirical equivalence between SQM and BM will be discussed. Finally, in the Conclusion, we will stress the scope of the obtained conclusions and the philosophical difficulties that still remain even after adopting BM for foundational purposes.

La concepción semántica de las teorías científicas supone la dependencia de los modelos respecto de las teorías. Algunos autores desafian tal supuesto a través del estudio de ciertos modelos concebidos como fenomenológicos. Sobre la base del análisis de los modelos atómicos y moleculares en quimica cuántica, en el presente artículo se argumentará en favor de una independencia de los modelos respecto de las teorías que no puede interpretarse como meramente histórica y relativa al contexto. Estos modelos ponen de manifiesto una independencia conceptual, constitutiva del proceso de modelización, que no resulta de una deficiencia contingente de la teoría, deficiencia que sería resuelta por el progreso futuro de la ciencia.The semantic view of scientific theories assumes the dependence of models on theories. Some authors challenge that assumption by means of the study of certain models conceived as phenomenological. On the basis of the analysis of atomic and molecular models in quantum chemistry, in this article we will argue for an independence of models from theories, which cannot be interpreted as merely historical and context relative. Those models shows a conceptual independence that is constitutive of the modeling process; such independence cannot be conceived as a result of a contingent deficiency of the theory used, deficiency that would be overcome by the future progress of science.

En abril de 2015 un equipo internacional de investigadores lograba medir, por primera vez, la primera energía de ionización del laurencio, un elemento superpesado de número atómico 103. El resultado experimental, publicado en la prestigiosa revista científica Nature, daba lugar a la reapertura de un antiguo debate que concierne a los elementos que deben formar parte del grupo 3 de la tabla periódica. El propósito de este trabajo es brindar una nueva línea de argumentación para elucidar este problema.