Goldstone boson counting in linear sigma models with chemical potential

We analyze the effects of finite chemical potential on spontaneous breaking of internal symmetries within the class of relativistic field theories described by the linear sigma model. Special attention is paid to the emergence of ``abnormal'' Goldstone bosons with quadratic dispersion relation. We show that their presence is tightly connected to nonzero density of the Noether charges, and formulate a general counting rule. The general results are demonstrated on an SU(3)xU(1) invariant model with an SU(3)-sextet scalar field, which describes one of the color-superconducting phases of QCD.Comment: 10 pages, REVTeX4, 4 eps figures, v2: general discussion in Sec. IV expanded and improved, references added, other minor corrections throughout the tex

From Sociology and Economics to World History

World History has only recently emerged as a distinctive and vibrant field of study. Its origins arose from a cross-fertilization of economics, history, and comparative sociology, and from particular conjunctions of people and places in the 1980s and 1990s. World historians now, thanks to unprecedented access to quantitative historical data and international networks of scholars, can develop increasingly precise, formal, and detailed accounts of changes and comparisons across historical periods. However, our goal is not to create new master narratives or theories that predict a grand historical trajectory for mankind; rather we seek to better understand the similarities and differences among societies, and the likely consequences of those similarities and differences.World History has only recently emerged as a distinctive and vibrant field of study. Its origins arose from a cross-fertilization of economics, history, and comparative sociology, and from particular conjunctions of people and places in the 1980s and 1990s. World historians now, thanks to unprecedented access to quantitative historical data and international networks of scholars, can develop increasingly precise, formal, and detailed accounts of changes and comparisons across historical periods. However, our goal is not to create new master narratives or theories that predict a grand historical trajectory for mankind; rather we seek to better understand the similarities and differences among societies, and the likely consequences of those similarities and differences

The Once and Future Middle Kingdom: China’s Return to Dominance in the Global Economy

Im 16. und 17. Jahrhundert führten alle Wege nach China. Die Nachfrage Europas nach chinesischer Seide, Keramik und Tee führte die europäischen Kaufleute in den Orient. Als Europa industrialisiert war, dominierten die Europäer den Welthandel, indem sie eine Reihe von Stützpunkten und Kolonien in Afrika, im Indischen Ozean und in China errichteten. Heute versucht China, diesen „devianten“ Trend umzukehren und China wieder zu seiner „normalen“ Position als führende Wirtschaftsmacht zu verhelfen. China strebt nach einer Führungsrolle in den Bereichen Wind- und Sonnenenergie, künstlicher Intelligenz, Elektromobilität und Quantencomputer, um die beherrschende Macht unter den Volkswirtschaften des 21. Jahrhunderts zu werden. Außerdem errichtet China eigene Stützpunkte quer durch den Indischen Ozean und nach Südeuropa, um seine Kontrolle über diese Handelsrouten wiederherzustellen. Wenn China Erfolghat, wird es die letzten zweihundert Jahre der Weltwirtschaftsgeschichte umkehren und seine frühere Rolle als Hauptakteur in der globalen Wirtschaft wiederherstellen.In the sixteenth and seventeenth centuries, all roads led to China. Europe’s demand for Chinese silks, ceramics, and tea led European traders to the Orient. Then as Europe industrialized, Europeans came to dominate world trade, building a string of bases and colonies around Africa, across the Indian Ocean, and in China. Today, China is seeking to reverse this “deviant” trend and restore China to its “normal” position as the world’s dominant economy. Seeking leadership in wind and solar power, artificial intelligence, electric vehicles, and quantum computing to become the dominant power among twenty-first century economies, China is also building its own set of bases across the Indian Ocean and into southern Europe to reassert its control of these trade routes. If China succeeds, it will reverse the last two hundred years of world economic history and reassert its earlier role as the core actor in the global economy

Uterine infusion of bacteria alters the transcriptome of bovine oocytes

Postpartum uterine infection reduces fertility in dairy cattle; however, the mechanisms of uterine infection‐mediated infertility are unknown. Paradoxically, infection‐induced infertility persists after the resolution of disease. Oocytes are a finite resource, which are present at various stages of development during uterine infection. It is likely that oocyte development is influenced by uterine infection‐induced changes to the follicular microenvironment. To better understand the impact of infection on oocyte quality we employed global transcriptomics of oocytes collected from heifers after receiving intrauterine infusion of pathogenic Escherichia coli and Trueperella pyogenes . We hypothesized that the oocyte transcriptome would be altered in response to intrauterine infection. A total of 452 differentially expressed genes were identified in oocytes collected from heifers 4 days after bacteria infusion compared to vehicle infusion, while 539 differentially expressed genes were identified in oocytes collected from heifers 60 days after bacteria infusion. Only 42 genes were differentially expressed in bacteria‐infused heifers at both Day 4 and Day 60. Interferon, HMGB1, ILK, IL‐6, and TGF‐beta signaling pathways were downregulated in oocytes collected at Day 4 from bacteria‐infused heifers, while interferon, ILK, and IL‐6 signaling were upregulated in oocytes collected at Day 60 from bacteria‐infused heifers. These data suggest that bacterial infusion alters the oocyte transcriptome differently at Day 4 and Day 60, suggesting different follicle stages are susceptible to damage. Characterizing the long‐term impacts of uterine infection on the oocyte transcriptome aids in our understanding of how infection causes infertility in dairy cattle

Spontaneous symmetry breaking in the linear sigma model at finite chemical potential: One-loop corrections

We investigate spontaneous symmetry breaking within the linear sigma model with the SU(2)xU(1) internal symmetry at finite chemical potential, which was suggested as a model for kaon condensation in the CFL phase of dense quark matter. One-loop corrections to the scalar field effective potential as well as its propagator are calculated. Particular attention is paid to the type-II Goldstone boson that appears in the Bose--Einstein condensed phase. Furthermore, we show that the type-I Goldstone boson -- the superfluid phonon -- is allowed to decay due to the nonlinearity of its dispersion relation at high momentum, and determine its decay width.Comment: 13 pages, REVTeX4, 37 eps figures; v2: substantial error in Sec. IV corrected, references added, other minor corrections; version to appear in Phys. Rev.

``Induced'' Super-Symmetry Breaking with a Vanishing Vacuum Energy

A new mechanism for symmetry breaking is proposed which naturally avoids the constraints following from the usual theorems of symmetry breaking. In the context of super-symmetry, for example, the breaking may be consistent with a vanishing vacuum energy. A 2+1 dimensional super-symmetric gauge field theory is explicitly shown to break super-symmetry through this mechanism while maintaining a zero vacuum energy. This mechanism may provide a solution to two long standing problems, namely, dynamical super-symmetry breaking and the cosmological constant problem.Comment: 12 pages, Late

A Quantum Adiabatic Evolution Algorithm Applied to Random Instances of an NP-Complete Problem

A quantum system will stay near its instantaneous ground state if the Hamiltonian that governs its evolution varies slowly enough. This quantum adiabatic behavior is the basis of a new class of algorithms for quantum computing. We test one such algorithm by applying it to randomly generated, hard, instances of an NP-complete problem. For the small examples that we can simulate, the quantum adiabatic algorithm works well, and provides evidence that quantum computers (if large ones can be built) may be able to outperform ordinary computers on hard sets of instances of NP-complete problems.Comment: 15 pages, 6 figures, email correspondence to [email protected] ; a shorter version of this article appeared in the April 20, 2001 issue of Science; see http://www.sciencemag.org/cgi/content/full/292/5516/47

Revisiting Critical Vortices in Three-Dimensional SQED

We consider renormalization of the central charge and the mass of the ${\cal N}=2$ supersymmetric Abelian vortices in 2+1 dimensions. We obtain ${\cal N}=2$ supersymmetric theory in 2+1 dimensions by dimensionally reducing the ${\cal N}=1$ SQED in 3+1 dimensions with two chiral fields carrying opposite charges. Then we introduce a mass for one of the matter multiplets without breaking N=2 supersymmetry. This massive multiplet is viewed as a regulator in the large mass limit. We show that the mass and the central charge of the vortex get the same nonvanishing quantum corrections, which preserves BPS saturation at the quantum level. Comparison with the operator form of the central extension exhibits fractionalization of a global U(1) charge; it becomes 1/2 for the minimal vortex. The very fact of the mass and charge renormalization is due to a "reflection" of an unbalanced number of the fermion and boson zero modes on the vortex in the regulator sector.Comment: 24 pages, 2 figures Minor modifications, reference adde

Stability of the magnetic Schr\"odinger operator in a waveguide

The spectrum of the Schr\"odinger operator in a quantum waveguide is known to be unstable in two and three dimensions. Any enlargement of the waveguide produces eigenvalues beneath the continuous spectrum. Also if the waveguide is bent eigenvalues will arise below the continuous spectrum. In this paper a magnetic field is added into the system. The spectrum of the magnetic Schr\"odinger operator is proved to be stable under small local deformations and also under small bending of the waveguide. The proof includes a magnetic Hardy-type inequality in the waveguide, which is interesting in its own

Engendering Accountability: Gender Crimes Under International Criminal Law

Gender crimes, such as rape, sexual assault, sexual slavery, and forced prostitution, have always been perpetrated during war, yet the laws of war have been slow to acknowledge these crimes and to bring their perpetrators to justice. This article examines the response of the International Criminal Tribunals for the Former Yugoslavia and Rwanda to this lacuna in international law, and analyzes the mainly positive developments they have made in this area in relation to the definition of rape and to the prosecution of gender crimes as crimes against humanity, war crimes, grave breaches of the Geneva Conventions, and genocide. It also traces the procedural safeguards instituted to facilitate the prosecution of gender crimes. The authors consider the way in which these advances have been taken forward in the Statute of the International Criminal Court, and the usefulness of other responses, such as the truth commissions in Bosnia and Yugoslavia, and the gacaca courts in Rwanda