Gauge invariant investigation of the nature of Confinement

We observe a strong correlation between the decrease in the number of action density peaks in SU(2) Yang-Mills configurations with cooling and that of the string tension. The nature and distribution of these peaks is investigated. The relationship with monopole currents after the abelian projection is also considered.Comment: uuencoded and Z-compressed file of the Postcript version of our contribution to LATTICE 95. 4 pages of text and 4 figure

Generalised L\"uroth expansions and a family of Minkowski's Question-Mark functions

The Minkowski's Question-Mark function is a singular homeomorphism of the unit interval that maps the set of quadratic surds into the rationals. This function has deserved the attention of several authors since the beginning of the twentieth century. Using different representations of real numbers by infinite sequences of integers, called $\alpha$-L\"uroth expansions, we obtain different instances of the standard shift map on infinite symbols, all of them topologically conjugated to the Gauss Map. In this note we prove that each of these conjugations share properties with the Minkowski's Question-Mark function: all of them are singular homeomorphisms of the interval, and in the "rational" cases, they map the set of quadratic surds into the set of rational numbers. In this sense, this family is a natural generalisation of the Minkowski's Question-Mark function

From Paris to Pittsburgh: U.S. State and Local Leadership in an Era of Trump

States and cities have long been leaders on clean energy and climate policy. Their work has informed development of federal policies including motor vehicle standards and the Clean Power Plan. With the election of President Trump and the increasingly severe impacts of climate change, subnational leadership has become even more important and urgent. In response, many states and cities have pledged to enact new policies to mitigate the effects of climate change and help communities adapt. This Article focuses on recent developments in subnational leadership on both climate mitigation and adaptation to demonstrate the breadth and depth of engagement by leading states and cities. It provides just some examples that illustrate how, despite the Trump Administration’s best efforts to dismantle federal environmental policies, many states and cities are fighting federal rollbacks and moving forward with their own policies to address climate change, promote a clean energy economy, and prepare for the consequences of a changing climate. Taken together, these efforts are important in keeping the United States within reach of the Paris Agreement targets. However, broader participation and meaningful federal action will be necessary to meet international commitments and avoid the most catastrophic consequences of climate change

Investing in America\u27s Surface Transportation Infrastructure: The Need for a Multi-Year Reauthorization Bill: Hearing Before the S. Comm. on Env\u27t & Pub. Works, 116th Cong., July 10, 2019

The Fourth National Climate Assessment, released in November 2018, described the serious impacts of climate change already being felt throughout the U.S., and made clear that the risks to communities all across the country are growing rapidly. These findings, along with those in the 2018 Intergovernmental Panel on Climate Change (IPCC) report should serve as an immediate call to action. Even if we manage to limit planetary warming to just 2 degrees Celsius, the world will still face increased chances of economic and social upheaval from more severe flooding, droughts, heatwaves, and other climate impacts as well as devastating environmental consequences, the IPCC report warns. The consensus from leading scientific research academies within the United States and internationally is clear: multiple lines of evidence indicate, and have indicated for years, that our atmosphere is warming, sea levels are rising, the magnitude and frequency of certain extreme weather events is increasing, and that human activity is the primary driver of climate change. As described in the IPCC Special Report, the consensus is that countries around the world must rapidly decarbonize their economies, cutting greenhouse gas emissions in half by 2030 and to near zero by 2050. The U.S. Department of Defense, and leaders within the defense and national security communities, have also recognized climate change as a “national security issue” that requires adapting military operations and planning to ensure readiness. Despite our understanding of the consequences we will face and the urgency to act, U.S. GHG emissions from fossil fuel combustion increased by 2.7 percent in 2018, according the Rhodium Group. Clearly more action is needed. While we all recognize the importance of transportation in our daily lives and for our economy, it is also important to recognize that the transportation sector is the largest contributor of GHG emissions in the United States, and is already facing significant impacts from climate change. There is an urgent need, therefore, to transition to a low-carbon and more resilient transportation system. Such a transition would not only reduce emissions and fight climate change, it also would bring additional important benefits, including protecting public health by reducing conventional air pollution, providing more mobility options, and driving innovation and economic growth through policy action and through public and private investment

Contested Modernities: Decolonial Knowledges, Transamerican Perspectives

Latin American Studie

Examining How Federal Infrastructure Policy Could Help Mitigate and Adapt to Climate Change: Hearing Before the H. Comm. on Transp. & Infrastructure, 116th Cong., Feb. 26, 2019 (Statement of Vicki Arroyo)

As the Fourth National Climate Assessment, released in November, describes, the United States is already experiencing serious impacts of climate change—and the risks to communities all across the country are growing rapidly. These findings, along with those in the 2018 Intergovernmental Panel on Climate Change (IPCC)report, are clear and should be a call to immediate action. Even if we manage to limit planetary warming to just 2 degrees C, the world will still face increased chances of economic and social upheaval from more severe flooding, droughts, heatwaves, and other climate impacts as well as devastating environmental consequences, the IPCC report warns. The scientific consensus as described in the IPCC Special Report is that countries around the world must rapidly decarbonize their economies, cutting greenhouse gas emissions in half by 2030 and to near zero by 2050. Yet the current trends are going in the wrong direction. Despite our increasing understanding of the narrowing window to act, U.S. GHG emissions increased by 3.4% in 2018, according to a January report from the Rhodium Group. Clearly more action is needed. The encouraging news is that many states and cities have committed to taking action. They are taking steps to reduce emissions through legislation, executive orders, and pledges made in collaborations such as the US Climate Alliance –now covering roughly half the US population and GDP. In my testimony, I will be focusing on the transportation sector, which is the largest contributor of GHG emissions in the United States, and is already facing significant impacts from climate change. Federal standards have been important in increasing efficiency and reducing emissions, yet transportation-sector emissions are increasing as more vehicle miles are driven, more freight is transported in trucks, and airline travel continues to grow. Transportation is becoming an increasingly large share of U.S. economy-wide emissions as the power sector decarbonizes as a result of market shifts and policy. There is an urgent need, therefore, to transition to a low-carbon transportation system. Such a transition would not only reduce emissions and fight climate change, it also would bring additional important benefits, including protecting public health by reducing conventional air pollution, providing more mobility options, and driving innovation and economic growth through policy action and through public and private investment

Vortex configurations in the large N limit

We study the properties of vortex-like configurations which are solutions of the SU(N) Yang-Mills classical equations of motion. We show that these solutions are concentrated along a two-dimensional wall with size growing with the number of colors.Comment: 13 pages, 4 postscript figure