MIT Briefing Book 2015 April Edition
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Inflation, Large Branes, and the Shape of Space
Inflation, Large Branes, and the Shape of Space Brett McInnes National University of Singapore email: [email protected] ABSTRACT Linde has recently argued that compact flat or negatively curved spatial sections should, in many circumstances, be considered typical in Inflationary cosmologies. We suggest that the “large brane instability” of Seiberg and Witten eliminates the negative candidates in the context of string theory. That leaves the flat, compact, three-dimensional manifolds — Conway’s platycosms. We show that deep theorems of Schoen, Yau, Gromov and Lawson imply that, even in this case, Seiberg-Witten instability can be avoided only with difficulty. Using a specific cosmological model of the Maldacena-Maoz type, we explain how to do this, and we also show how the list of platycosmic candidates can be reduced to three. This leads to an extension of the basic idea: the conformal compactification of the entire Euclidean spacetime also has the topology of a flat, compact, four-dimensional space. arXiv:hep-th/0410115v2 19 Oct 2004 1. Nearly Flat or Really Flat? Linde has recently argued [1] that, at least in some circumstances, we should regard cosmological models with flat or negatively curved compact spatial sections as the norm from an Inflationary point of view. Here we wish to argue that cosmic holography, in the novel form proposed by Maldacena and Maoz [2], gives a deep new interpretation of this idea, and also sharpens it very considerably to exclude the negative case. This focuses our attention on cosmological models with flat, compact spatial sections. Current observations [3] show that the spatial sections of our Universe [as defined by observers for whom local isotropy obtains] are fairly close to being flat: the total density parameter Ω satisfies Ω = 1.02 0.02 at 95% confidence level, if we allow the imposition ± of a reasonable prior [4] on the Hubble parameter. -
March 12, 2008 (Download PDF)
Volume 52, Number 19 Wednesday, March 12, 2008 TechTalk S ERVING THE MIT CO mm UNI T Y MIT boosts aid for students Increases number of undergraduates who can attend tuition-free More MIT students will have their tuition and fees completely covered next year under a series of financial aid enhancements that the Institute unveiled March 7. Under the new plan, families earning IMAGE / ELLENZWEIG ARCHITECTURE | PLANNING less than $75,000 a year will have all tuition covered. For parents with total annual David H. Koch Institute for Integrative Cancer Research groundbreaking income below $75,000 and typical assets, MIT will ensure that all tuition charges are An artist’s rendering of the new David H. Koch Institute for Integrative Cancer Research at MIT, which will be constructed at the corner covered with an MIT scholarship, federal of Main and Ames streets. Groundbreaking on the research institution was held on March 7, for more on the event see page 8. and state grants and/or outside scholar- ship funds. Nearly 30 percent of MIT stu- dents fall into this tuition-free category. For families earning less than $75,000 a year, MIT will eliminate the student loan Marine bacteria’s mealtime dash is a swimming success expectation. MIT will no longer expect Denise Brehm take up nutrients before they students from families with total annual Civil and Environmental Engineering undergo chemical changes. A income below $75,000 and typical assets to paper published in the March 10 take out loans to cover expenses beyond online edition of the Proceedings tuition. -
Eternal Inflation and Its Implications
IOP PUBLISHING JOURNAL OF PHYSICS A: MATHEMATICAL AND THEORETICAL J. Phys. A: Math. Theor. 40 (2007) 6811–6826 doi:10.1088/1751-8113/40/25/S25 Eternal inflation and its implications Alan H Guth Center for Theoretical Physics, Laboratory for Nuclear Science, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA E-mail: [email protected] Received 8 February 2006 Published 6 June 2007 Online at stacks.iop.org/JPhysA/40/6811 Abstract Isummarizetheargumentsthatstronglysuggestthatouruniverseisthe product of inflation. The mechanisms that lead to eternal inflation in both new and chaotic models are described. Although the infinity of pocket universes produced by eternal inflation are unobservable, it is argued that eternal inflation has real consequences in terms of the way that predictions are extracted from theoretical models. The ambiguities in defining probabilities in eternally inflating spacetimes are reviewed, with emphasis on the youngness paradox that results from a synchronous gauge regularization technique. Although inflation is generically eternal into the future, it is not eternal into the past: it can be proven under reasonable assumptions that the inflating region must be incomplete in past directions, so some physics other than inflation is needed to describe the past boundary of the inflating region. PACS numbers: 98.80.cQ, 98.80.Bp, 98.80.Es 1. Introduction: the successes of inflation Since the proposal of the inflationary model some 25 years ago [1–4], inflation has been remarkably successful in explaining many important qualitative and quantitative properties of the universe. In this paper, I will summarize the key successes, and then discuss a number of issues associated with the eternal nature of inflation. -
Section 1: MIT Facts and History
1 MIT Facts and History Economic Information 9 Technology Licensing Office 9 People 9 Students 10 Undergraduate Students 11 Graduate Students 12 Degrees 13 Alumni 13 Postdoctoral Appointments 14 Faculty and Staff 15 Awards and Honors of Current Faculty and Staff 16 Awards Highlights 17 Fields of Study 18 Research Laboratories, Centers, and Programs 19 Academic and Research Affiliations 20 Education Highlights 23 Research Highlights 26 7 MIT Facts and History The Massachusetts Institute of Technology is one nologies for artificial limbs, and the magnetic core of the world’s preeminent research universities, memory that enabled the development of digital dedicated to advancing knowledge and educating computers. Exciting areas of research and education students in science, technology, and other areas of today include neuroscience and the study of the scholarship that will best serve the nation and the brain and mind, bioengineering, energy, the envi- world. It is known for rigorous academic programs, ronment and sustainable development, informa- cutting-edge research, a diverse campus commu- tion sciences and technology, new media, financial nity, and its long-standing commitment to working technology, and entrepreneurship. with the public and private sectors to bring new knowledge to bear on the world’s great challenges. University research is one of the mainsprings of growth in an economy that is increasingly defined William Barton Rogers, the Institute’s founding pres- by technology. A study released in February 2009 ident, believed that education should be both broad by the Kauffman Foundation estimates that MIT and useful, enabling students to participate in “the graduates had founded 25,800 active companies. -
8.962 General Relativity, Spring 2017 Massachusetts Institute of Technology Department of Physics
8.962 General Relativity, Spring 2017 Massachusetts Institute of Technology Department of Physics Lectures by: Alan Guth Notes by: Andrew P. Turner May 26, 2017 1 Lecture 1 (Feb. 8, 2017) 1.1 Why general relativity? Why should we be interested in general relativity? (a) General relativity is the uniquely greatest triumph of analytic reasoning in all of science. Simultaneity is not well-defined in special relativity, and so Newton's laws of gravity become Ill-defined. Using only special relativity and the fact that Newton's theory of gravity works terrestrially, Einstein was able to produce what we now know as general relativity. (b) Understanding gravity has now become an important part of most considerations in funda- mental physics. Historically, it was easy to leave gravity out phenomenologically, because it is a factor of 1038 weaker than the other forces. If one tries to build a quantum field theory from general relativity, it fails to be renormalizable, unlike the quantum field theories for the other fundamental forces. Nowadays, gravity has become an integral part of attempts to extend the standard model. Gravity is also important in the field of cosmology, which became more prominent after the discovery of the cosmic microwave background, progress on calculations of big bang nucleosynthesis, and the introduction of inflationary cosmology. 1.2 Review of Special Relativity The basic assumption of special relativity is as follows: All laws of physics, including the statement that light travels at speed c, hold in any inertial coordinate system. Fur- thermore, any coordinate system that is moving at fixed velocity with respect to an inertial coordinate system is also inertial. -
Advanced Imaging Technology
MICROELECTRONICS LABORATORY SPOTLIGHT ON Advanced Imaging Technology KEY FEATURES • World’s lowest readout noise, Digital focal plane array. highest quantum efficiency CCD imagers MIT Lincoln Laboratory has long been a leader • Geiger-mode (GM) APDs with in advanced imaging for defense and scientific single-photon sensitivity and applications. Our imaging capabilities are broadly noiseless digital readout classified into three categories: charge-coupled • DFPAs containing a complete devices (CCDs), avalanche photodiodes (APDs), analog-to-digital converter in every pixel, enabling image and digital focal plane array (DFPA) technology. processing on the focal plane Technology in Support of National Security www.ll.mit.edu SPOTLIGHT ON Advanced Imaging Technology Charge-Coupled Devices Our CCDs are used in ground, air, and spaced-based applications of interest to the government and scientific research community. These CCDs span a range of wavelengths including visible, near infrared, ultraviolet, and soft X-ray. Among imagers employing our CCDs are the two 1.4-billion- pixel Panoramic Survey Telescope and Rapid Response System’s (Pan-STARRS) focal plane arrays, the largest focal planes fabricated to date, and the Space Surveillance Telescope’s curved focal planes that provide a uniform and wide field of view. Optical micrograph of back-illuminated CCD wafer. Geiger-Mode Avalanche Photodiodes For passive imaging, the noiseless readout of our GM-APDs enables photon counting, providing both the requisite sensitivity for low-light applications and photon count rates for high-speed imaging. APDs are also employed in active ladar systems to time-stamp photon arrival times, enabling 3D imaging in compact airborne systems. We also fabricate APD arrays on compound semiconductor materials, expanding these capabilities further into the infrared. -
Classmate Biographies
CLASSMATE BIOGRAPHIES 38 David Jeffrey Abeshouse Course: VIII Tell us about your recollections of your student years at MIT: I lived in Student House, which is essentially on the B.U. campus. If I recall correctly, it was a mile walk to MIT. That walk, in all kinds of weather, is one of my strongest, if not favorable, memories of my years there. Unless something unusual happened, I made the round trip just once a day. Student House is near Kenmore Square and Fenway Park. The gates to Fenway would open in the sixth inning then, and there were mostly afternoon games, so we would go up to the park occasionally to see, for free, the last three innings. We saw Ted Williams regularly. Student House was also next to the Charles, and it was fun to go down near the river in pleasant weather. I struggled to survive academically, but I did it. I don't remember the name of the professor who lectured our freshman chemistry course, but he spoke in a monotone, and I fell asleep practically every time. I finally went to a different lecture section. I have a poor sense of direction and was regularly lost around the campus and often rushing to get to class. Once in my sophomore year I was rushing and rounded a corner and almost flattened Norbert Wiener. He had a large abdomen, and, from my point of view, the collision was soft. The work on my senior paper was done in building 20. That was a fine place to spend a lot of time. -
MIT Lincoln Laboratory Division and Group Descriptions
MIT Lincoln Laboratory Division and Group Descriptions October 2012 AIR AND MISSILE DEFENSE TECHNOLOGY DIVISION 3 The Air and Missile Defense Technology Division’s role is to work with government, industry, and laboratories to develop an integrated air and missile defense system. The division’s main focus is investigating system concepts, developing technology, building prototypes, and conducting measurements to support the development of radar and optical sensors, interceptors, and networks for air and missile defense systems. A strong emphasis is placed on partnerships and the transfer of technology to industry. Group 31—Systems and Architectures The Systems and Architectures Group examines near- and long-term technology opportunities for charting the future development of U.S. air and missile defenses. As the country proceeds with the deployment of new missile defense systems, Lincoln Laboratory and this group are working on the next generation of architectures and technologies. The group investigates advanced radar concepts, new infrared sensors, missile designs, space-based platforms, and future distributed command-and-control software to help identify opportunities to develop, test, and deploy these technologies. The group also devotes considerable effort to investigating the impact of various countermeasures on U.S. air and missile defense systems, particularly with respect to various types of electronic warfare. Staff members in the group have a wide variety of backgrounds, including physics, electrical engineering, mathematics, and astrodynamics. Group 33—Advanced Sensor Systems and Test Beds The Advanced Sensor Systems and Test Beds Group supports the Department of Defense by designing and developing modern sensor systems and components to support airborne air defense radars as well as the ballistic missile defense system. -
Sacred Rhetorical Invention in the String Theory Movement
University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Communication Studies Theses, Dissertations, and Student Research Communication Studies, Department of Spring 4-12-2011 Secular Salvation: Sacred Rhetorical Invention in the String Theory Movement Brent Yergensen University of Nebraska-Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/commstuddiss Part of the Speech and Rhetorical Studies Commons Yergensen, Brent, "Secular Salvation: Sacred Rhetorical Invention in the String Theory Movement" (2011). Communication Studies Theses, Dissertations, and Student Research. 6. https://digitalcommons.unl.edu/commstuddiss/6 This Article is brought to you for free and open access by the Communication Studies, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Communication Studies Theses, Dissertations, and Student Research by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. SECULAR SALVATION: SACRED RHETORICAL INVENTION IN THE STRING THEORY MOVEMENT by Brent Yergensen A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy Major: Communication Studies Under the Supervision of Dr. Ronald Lee Lincoln, Nebraska April, 2011 ii SECULAR SALVATION: SACRED RHETORICAL INVENTION IN THE STRING THEORY MOVEMENT Brent Yergensen, Ph.D. University of Nebraska, 2011 Advisor: Ronald Lee String theory is argued by its proponents to be the Theory of Everything. It achieves this status in physics because it provides unification for contradictory laws of physics, namely quantum mechanics and general relativity. While based on advanced theoretical mathematics, its public discourse is growing in prevalence and its rhetorical power is leading to a scientific revolution, even among the public. -
2-Page-Tree-Saving Format
M P Corp. SS&C Conf. .O. Box 8236 Box .O. onterey, CA 93943 CA onterey, FORTY-SIXTH ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS AND COMPUTERS November 4–7, 2012 Asilomar Hotel and Conference Grounds Technical Co-sponsor FORTY-SIXTH Welcome from the General Chairman ASILOMAR CONFERENCE ON Prof. Miloš Doroslovački SIGNALS, SYstEMS & COMPUTERS The George Washington University Welcome to this unique conference. Many of us come here from year to year to be exposed to new ideas and to do brainstorming Organized in cooperation with about them in an informal and relaxed way, surrounded by magnificent nature. To cite John Steinbeck, Nobel Prize laureate in literature and local to this part of California: “Ideas are like ATK SPACE SYstEMS rabbits. You get a couple and learn how to handle them, and pretty Monterey, California soon you have a dozen.” I am sure that the conference will be stimulating for your future professional endeavors. and Technical Co-sponsor The biggest credit for the intellectual value of the conference goes to the Technical Program Chair Erik G. Larsson and his team, made of Technical Area Chairs and Session Chairs, as well as to IEEE SIGNAL PROCESSING SOCIETY all of you who contributed with papers. Erik and his team prepared an excellent program of 435 papers, including 171 invited, and a tutorial session. For their outstanding work in shaping the technical program, I would like to thank Erik and the Technical Area Chairs: Henk Wymeersch, Gerald Matz, Vincent Poor, Erchin Serpedin, Marius Pesavento, Arye Nehorai, Joseph Cavallaro, Ghassan CONFERENCE COMMITTEE AlRegib and Phil Schniter. -
Stouffer's Starts Running Morss Hall Food Service
NEWSPAPEROF THE UNDERGRADUATES OF THE ASSACHUSETTS INSTITUE OF TECHNLOGY OFFICIAL .. NWSPPEROF THE UNDERGRADUATES OF THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY OL. LXKVII NOo. I CAMBRIDGE, MASSACHUSETTS, FRIDAY, FEBRUARY 8, 1957 5 CENT i r i -4 -- , - I -- , ry Library Guards Stouffer's Starts Running o Curb Book Thefts aut Chief Woe Is $s Morss Hall Food Service "I honestly don't lknow of any food- about the deterioration of Commons "We are the last major urban in- meals, Mr. Maclaurin said that about itution to initiate such a plan," service company which serves as good food at such low prices." In this way, the only appreciable change made tes Professor W. N. Locke, Direc- was in limiting the number of bev- r of the Institute Libraries, of the R. Colin Maclaurin, Director of Gen- eral Services, describes Stouffer's, elages served on Commons to one in- ew library "Book checking" policy. stead of three, as previously. This -ting. the inconvenience to Institute the firm which will manage the din- ing service in Morss Hall and Pritch- and the other minor changes in the udents and faculty of the some five food were necessary in view of the ousand odd dollars of "missing" et Lounge this term. In a few weeks, Stouffer's recipes rising costs of food and labor within oks which plague the system annu- the last few years. For example, the ly, Locke emphasized the "frustrat- will be used to prepare the food serv- ed in Walker Memorial, and the firm salaries of the employees were re- g" nature of book disappearances cently raised by 10%. -
2016 Annual Report (Pdf)
MIT LINCOLN LABORATORY LINCOLN MIT Follow MIT Lincoln Laboratory online. Facebook: MIT Lincoln Laboratory LinkedIn: http://www.linkedin.com/company/ mit-lincoln-laboratory Twitter: @MITLL YouTube: MIT Lincoln Laboratory Instagram: https://www.instagram.com/ lincoln_laboratory/ 2016 Annual2016 Report MIT Lincoln Laboratory 2016 ANNUAL REPORT www.ll.mit.edu Communications and Community Outreach Office: 781.981.4204 Approved for public release: distribution unlimited. This material is based upon work supported under Air Force Contract No. FA8721-05-C-0002 and/or FA8702-15-D-0001. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the U.S. Air Force. TECHNOLOGY IN SUPPORT OF NATIONAL SECURITY © 2016 Massachusetts Institute of Technology TECHNOLOGY IN SUPPORT OF NATIONAL SECURITY Massachusetts Institute of Technology Lincoln Space Surveillance Complex, Westford, Massachusetts MIT Lincoln Laboratory Reagan Test Site, Kwajalein Atoll, Marshall Islands MIT LINCOLN LABORATORY 2016 Table of Contents MISSION 2 Leadership Technology in Support 3 Organizational Changes of National Security 4 Letter from the Director 5 Vision, Values, and Strategic Directions MIT Lincoln Laboratory employs some of the nation’s best technical talent to support system and 7 Technology Innovation technology development for national security needs. 8 Swarm of Miniature Aircraft Autonomously Maintains Flight Formation Principal core competencies are sensors, infor- 10 Technology Investments mation extraction (signal processing and embedded 16 Achieving a Near-Ideal Laser Beam computing), communications, integrated sensing, and 18 Localizing Ground-Penetrating Radar decision support. Nearly all of the Lincoln Laboratory 20 Discovering the Vast Asteroid Population efforts are housed at its campus on Hanscom Air 22 Technology Transfer Force Base in Massachusetts.