Particle production from marginally trapped surfaces of general spacetimes

We provide a general formalism that allows to analyze the phenomenon of tunneling in arbitrary spacetimes. We show that a flux of particles produced by tunneling through general marginally trapped surfaces may be perceived by some privileged observers. We discuss how this particle perception can be related to Hawking/Unruh radiation in specific cases. Our approach naturally leads to an expression for the effective surface gravity of marginally trapped surfaces. The procedure is applicable to general astrophysical and cosmological dynamical situations. Some practical examples for known and new cases are provided.Comment: 24 pages, 2 figures. Section 4.2, concerning the analysis of the Kerr-Vaidya solution, has been rewritten, correcting mistakes in previous versions. The corrected calculations do support our claims. A corrigendum has also been sent to CQG. New references added. Some of the mistakes in previous versions are actually common and spread in the literature on the Kerr-Vaidya solutio

Exchange rate dynamics in crawling-band systems

In this note we show that an exchange rate crawling-band system can borrow a portion of those aspects of a target zone that lead to its stabilizing effects on the exchange rate, depending on the relationship between the crawl rate and the drift of the fundamentals process. If the crawl rate is sufficiently high (with respect to the drift), the crawling-band is similar to a free float regime. As the crawl rate decreases, the crawling-band system collapses to a standard target zone.crawling band

Personal Reflections / 3.1.18

Even with the distance created by time between the shooting in Parkland, Florida and today, I still choke up when I consider the loss of life that happened at the Marjory Stoneman Douglas High School on February 14, Valentine’s Day, two weeks ago. Ponder their lives, their unfulfilled potential and their unrealized dreams. Consider how we should live in this society. Determine what action you can take

Personal Reflections / 12.20.18

Today as our IMSA students depart from their IMSA home to spend winter break at their other home, I want to wish them and their families a very joy-filled winter break. I know that our staff, including myself and the faculty, look forward to enjoying the holidays with our respective families. Last Friday, our students, led ably by our Music Faculty Mary Beth McCarthy and Emily Cooley, put on a spectacular music program, Sleigh Ride Around the World . Many family members who joined us can attest to the quality and variety of the performance. I was so impressed with the diversity of songs, composers, and instruments represented in the program. This diversity reminded me that I have not yet focused on Equity and Excellence in these Personal Reflections. As you might recall, I am using each issue of this year\u27s Personal Reflections to focus on one IMSA Priority. Today, I want to focus on our Equity and Excellence priority

ISSF 2018 Opening Ceremony

For the past 14 year, the International Student Science Fair has convened talented students and their amazing teachers and school leaders to share scientific knowledge and develop life long friendships. This year, we have 90 Students, 30 Teachers, and 32 Principals or school leaders representing 18 countries here in the USA! Five continents are reflected here in this room! The theme for this year\u27s ISSF is to significantly influence life on our planet through cooperation and collaboration. The phrase, “significantly influence life on our planet,” has its origin in IMSA’s philosophy coined by our founder, Leon Lederman, Nobel Prize Physicist, who said, If we do what we know and feel is right, it is bound to happen that among our graduates there will be numbered scientists, engineers, and those who go on to earn degrees in law and letters. There are likely to be those few who create new intellectual worlds, cure a dreaded human ailment, or in some other way significantly influence life on our planet. Our philosophy will be to treat our charges as if each one is capable of this extraordinary achievement

Convocation 2015: Opening Remarks

“Life is just a minute, only sixty seconds in it. Forced upon you, can’t refuse it, didn’t seek it, didn’t choose it, But it’s up to you to use it. You must suffer if you lose it. Give an account if you abuse it. Just a tiny little minute, But eternity is in it.” ~Dr. Benjamin E. May