Quantum mechanics is about quantum information

I argue that quantum mechanics is fundamentally a theory about the representation and manipulation of information, not a theory about the mechanics of nonclassical waves or particles. The notion of quantum information is to be understood as a new physical primitive -- just as, following Einstein's special theory of relativity, a field is no longer regarded as the physical manifestation of vibrations in a mechanical medium, but recognized as a new physical primitive in its own right.Comment: 17 pages, forthcoming in Foundations of Physics Festschrift issue for James Cushing. Revised version: some paragraphs have been added to the final section clarifying the argument, and various minor clarifying remarks have been added throughout the tex

Bestimmung der ernährungsphysiologischen Qualität von Öko-Produkten anhand des antioxidativen Potentials der Lebensmittel

Problemstellung: Die Diskussionen über sichere Lebensmittel (u.a. Rückstände von Pestiziden) im letzten Jahrzehnt hat das Verbraucherverhalten verändert. Viele Verbraucher bevorzugen ökologisch erzeugte Lebensmittel. Allerdings gibt es bis heute noch nicht ausreichende wissenschaftliche Daten dazu, ob ökologisch erzeugte Lebensmittel tatsächlich ernährungsphysiologisch hochwertiger sind als konventionell produzierte. Sekundären Pflanzenstoffen aus Obst und Gemüse (Carotinoiden, Polyphenole) kommt im Allgemeinen eine hohe gesundheitliche Bedeutung zu. Die in der Literatur beschriebenen protektiven Effekte auf entzündliche, atherosklerotische und tumorigene Prozesse werden u.a. auf ihr antioxidatives Potenzial zurückgeführt. Ziel der Studie war es daher zu untersuchen, ob sich der Gehalt an Carotinoiden und Polyphenolen und die antioxidative Kapazität in Lebensmitteln aus konventionellem und ökologischem Anbau unterscheidet. Darüber hinaus wurden drei humane Interventionsstudien durchgeführt, die klären sollten, ob die unterschiedlichen Anbauvarianten (ökologisch/konventionell) Einfluss auf die Bioverfügbarkeit der sekundären Pflanzenstoffe und den antioxidativen Status in vivo haben. Methodik: Im Rahmen des Projektes wurden Äpfel, Karotten und Weizenvollkorn der Erntejahre 2004, 2005 und 2006 aus kontrollierten Anbauversuchen untersucht. Die Gehalte an sekundären Pflanzenstoffen in vitro und in vivo wurden mittels HPLC/DAD/MS quantifiziert. Die antioxidativen Kapazitäten in vivo und in vitro wurden mit drei unterschiedlichen Testsystemen analysiert. Ergebnisse: Die Ergebnisse zeigen, dass die Anbauweise (ökologisch/konventionell) die Bildung von sekundären Pflanzenstoffen und das antioxidatives Potenzial in den untersuchten Lebensmitteln beeinflussen kann. Für die Öko-Produkte kann ein leicht höherer Gehalt und antioxidatives Potenzial bestimmt werden. In den durchgeführten Humanstudien, konnten keine Unterschiede in der Bioverfügbarkeit von Carotinoiden und Polyphenolen zwischen ökologisch und konventionell angebauten Äpfeln bzw. Karotten gezeigt werden. Schlussfolgerung: Die beobachteten Unterschiede im Gehalt an sekundären Pflanzenstoffen sowie im antioxidativen Potenzial zwischen den Anbauweisen sind klein und besitzen geringe ernährungsphysiologische Relevanz

Parity proofs of the Bell-Kochen-Specker theorem based on the 600-cell

The set of 60 real rays in four dimensions derived from the vertices of a 600-cell is shown to possess numerous subsets of rays and bases that provide basis-critical parity proofs of the Bell-Kochen-Specker (BKS) theorem (a basis-critical proof is one that fails if even a single basis is deleted from it). The proofs vary considerably in size, with the smallest having 26 rays and 13 bases and the largest 60 rays and 41 bases. There are at least 90 basic types of proofs, with each coming in a number of geometrically distinct varieties. The replicas of all the proofs under the symmetries of the 600-cell yield a total of almost a hundred million parity proofs of the BKS theorem. The proofs are all very transparent and take no more than simple counting to verify. A few of the proofs are exhibited, both in tabular form as well as in the form of MMP hypergraphs that assist in their visualization. A survey of the proofs is given, simple procedures for generating some of them are described and their applications are discussed. It is shown that all four-dimensional parity proofs of the BKS theorem can be turned into experimental disproofs of noncontextuality.Comment: 19 pages, 11 tables, 3 figures. Email address of first author has been corrected. Ref.[5] has been corrected, as has an error in Fig.3. Formatting error in Sec.4 has been corrected and the placement of tables and figures has been improved. A new paragraph has been added to Sec.4 and another new paragraph to the end of the Appendi

Quantum theory of successive projective measurements

We show that a quantum state may be represented as the sum of a joint probability and a complex quantum modification term. The joint probability and the modification term can both be observed in successive projective measurements. The complex modification term is a measure of measurement disturbance. A selective phase rotation is needed to obtain the imaginary part. This leads to a complex quasiprobability, the Kirkwood distribution. We show that the Kirkwood distribution contains full information about the state if the two observables are maximal and complementary. The Kirkwood distribution gives a new picture of state reduction. In a nonselective measurement, the modification term vanishes. A selective measurement leads to a quantum state as a nonnegative conditional probability. We demonstrate the special significance of the Schwinger basis.Comment: 6 page

Isomorphism between the Peres and Penrose proofs of the BKS theorem in three dimensions

It is shown that the 33 complex rays in three dimensions used by Penrose to prove the Bell-Kochen-Specker theorem have the same orthogonality relations as the 33 real rays of Peres, and therefore provide an isomorphic proof of the theorem. It is further shown that the Peres and Penrose rays are just two members of a continuous three-parameter family of unitarily inequivalent rays that prove the theorem.Comment: 7 pages, 2 Tables. A concluding para and 9 new references have been added to the second versio

Carbon cycling in Lake Superior

Carbon (C) cycling in Lake Superior was studied within the Keweenaw Interdisciplinary Transport Experiment in Superior (KITES) project to assess (1) whether the lake is net heterotrophic, (2) sources, sinks and residence time for dissolved organic carbon (DOC), (3) importance of terrigenous organic C subsidies, and (4) factors limiting C flow through bacteria. During 3 years of fieldwork, measurements were made of spatial and temporal distributions of C pools and rates of photosynthesis, community respiration, and bacterial production. Measurements were made of the composition of dissolved organic matter (DOM), rates of DOM photolysis, lability of DOM toward microbial consumption, and river inputs of DOM. All measurements suggest the lake is net heterotrophic. The C:N ratios of DOM suggest that it is primarily of terrigenous origin, but other characteristics (size distribution, UV absorption) point to the presence of autochthonous DOM and to alteration of terrigenous material. The lake mass balance indicates that the residence time (∼8 years) of the DOC pool (17 Tg) is short relative to the hydrologic residence time (170 years). The known flux of terrigenous DOC (∼1 Tg/yr) is too low to support annual bacterial carbon demand (6–38 Tg/yr), but microbial respiration is the major sink for terrigenous DOC. A rapidly cycling, autochthonous DOC pool must exist. Microbial activity was correlated with temperature, phosphorus availability, and DOC concentration but not with photosynthesis rates. Measurements of respiration (∼40 Tg/yr), photosynthesis (2–7 Tg/yr), and bacterial production (0.5–2 Tg/yr) are not all mutually compatible and result in a discrepancy in the organic carbon budget

Perioperative cardiac events in endovascular repair of complex aortic aneurysms and association with preoperative studies

BackgroundEndovascular repair of complex aortic aneurysms (CAAs) can be performed in high-risk individuals, yet is still associated with significant morbidity, including spinal cord ischemia, cardiac complications, and death. This analysis was undertaken to better define the cardiac risk for CAA.MethodsA prospective database of patients undergoing thoracoabdominal or juxtarenal aortic aneurysm repair with branched and fenestrated endografts was used to retrospectively determine the number of cardiac events, defined as myocardial infarction (MI), atrial fibrillation (AF), and ventricular arrhythmia (VA), that occurred ≤30 days of surgery. Postoperative serial troponin measurements were performed in 266 patients. Any additional available cardiac information, including preoperative echocardiography, physiologic stress tests, and history of cardiac disease, was obtained from medical records. The efficacy of preoperative stress testing and the association of various echo parameters were evaluated in the context of cardiac outcomes using univariable and multivariable logistic regression models.ResultsBetween August 2001 and December 2007, 395 patients underwent endovascular repair of a thoracoabdominal or juxtarenal aortic aneurysm. The incidence of AF, VA, and 30-day cardiac-related death was 9%, 3%, and 2%, respectively. Overall 30-day mortality was 6%. Univariable analysis showed the presence of mitral annulus calcification was associated with MI (odds ratio [OR], 3.5; 95% confidence interval [CI], 0.9-13.8; P = .07). Left atrium cavity area, ejection fraction, left ventricle mass, and left ventricular mass index were univariably associated with the presence of VA. Multivariable analysis showed only the left atrium cavity area was independently associated with VA (OR, 1.2; 95% CI, 1.0-1.5; P = .07). Stress test was done in 179 patients. Negative stress test results occurred in 152 (85%), of whom 9 (6%) sustained an MI during the 30-day perioperative course. MI occurred in 2 of the 27 patients (7%) who had a positive stress test result.ConclusionsEndovascular repair of CAA can be performed in high-risk individuals but is associated with significant cardiac risk. It remains difficult to risk stratify patients using preoperative stress testing. Echo evaluation may help to identify patients who may be more likely to develop ventricular arrhythmias in the postoperative period and thus warrant closer monitoring. Postoperative troponin monitoring of all patients undergoing repair of CAA is warranted given the overall risk of MI

Quantum models of classical mechanics: maximum entropy packets

In a previous paper, a project of constructing quantum models of classical properties has been started. The present paper concludes the project by turning to classical mechanics. The quantum states that maximize entropy for given averages and variances of coordinates and momenta are called ME packets. They generalize the Gaussian wave packets. A non-trivial extension of the partition-function method of probability calculus to quantum mechanics is given. Non-commutativity of quantum variables limits its usefulness. Still, the general form of the state operators of ME packets is obtained with its help. The diagonal representation of the operators is found. A general way of calculating averages that can replace the partition function method is described. Classical mechanics is reinterpreted as a statistical theory. Classical trajectories are replaced by classical ME packets. Quantum states approximate classical ones if the product of the coordinate and momentum variances is much larger than Planck constant. Thus, ME packets with large variances follow their classical counterparts better than Gaussian wave packets.Comment: 26 pages, no figure. Introduction and the section on classical limit are extended, new references added. Definitive version accepted by Found. Phy

Realism and the wave-function

Realism -- the idea that the concepts in physical theories refer to 'things' existing in the real world -- is introduced as a tool to analyze the status of the wave-function. Although the physical entities are recognized by the existence of invariant quantities, examples from classical and quantum physics suggest that not all the theoretical terms refer to the entities: some terms refer to properties of the entities, and some terms have only an epistemic function. In particular, it is argued that the wave-function may be written in terms of classical non-referring and epistemic terms. The implications for realist interpretations of quantum mechanics and on the teaching of quantum physics are examined.Comment: No figure

Quantum measurement problem and cluster separability

A modified Beltrametti-Cassinelli-Lahti model of measurement apparatus that satisfies both the probability reproducibility condition and the objectification requirement is constructed. Only measurements on microsystems are considered. The cluster separability forms a basis for the first working hypothesis: the current version of quantum mechanics leaves open what happens to systems when they change their separation status. New rules that close this gap can therefore be added without disturbing the logic of quantum mechanics. The second working hypothesis is that registration apparatuses for microsystems must contain detectors and that their readings are signals from detectors. This implies that separation status of a microsystem changes during both preparation and registration. A new rule that specifies what happens at these changes and that guarantees the objectification is formulated and discussed. A part of our result has certain similarity with 'collapse of the wave function'.Comment: 31 pages, no figure. Published versio