He sounds important in his field even if his achievements are out of my range even of understanding.
Joseph Polchinski (May 16, 1954 – February 2, 2018) was an American theoretical physicist and string theorist.[2][3]
Polchinski graduated from Canyon del Oro High School in Tucson, Arizona in 1971, obtained his B.S. degree from Caltech in 1975, and his Ph.D. from the University of California, Berkeley in 1980 under the supervision of Stanley Mandelstam. After postdoctoral positions at SLAC (1980–82) and Harvard (1982–84) he was professor at the University of Texas at Austin from 1984 to 1992. Since 1992 he has been professor in the Physics Department of the University of California, Santa Barbara and a permanent member of the Kavli Institute for Theoretical Physics there.[4]
Polchinski wrote the two-volume textbook String Theory, published in 1998. Among his many contributions to theoretical physics, D-branes are the best known. In 2008 he won the Dirac Medal for his work in superstring theory.[5] He won the 2017 Fundamental Physics Prize.[6]
In an unpublished communication to Kip Thorne circa 1990, commenting on the Novikov self-consistency principle (in relation to sending objects or people through a traversable wormhole into the past, and the time paradoxes that could result), Polchinski raised a potentially paradoxical situation involving a billiard ball sent through a wormhole which sends it back in time. In this scenario, the ball is fired into a wormhole at an angle such that, if it continues along that path, it will exit the wormhole in the past at just the right angle to collide with its earlier self, thereby knocking it off course and preventing it from entering the wormhole in the first place. Thorne dubbed this problem "Polchinski's paradox" in 1994.[7] Later students of the whimsical problem came up with solutions which managed to avoid any inconsistencies, by having the ball emerge from the future at a different angle than the one used to generate the paradox, and deliver its younger self a glancing blow instead of knocking it completely away from the wormhole, a blow which changes its trajectory in just the right way so that it will travel back in time with the angle required to deliver its younger self this glancing blow.[7]
In an unpublished communication to Kip Thorne circa 1990, commenting on the Novikov self-consistency principle (in relation to sending objects or people through a traversable wormhole into the past, and the time paradoxes that could result), Polchinski raised a potentially paradoxical situation involving a billiard ball sent through a wormhole which sends it back in time. In this scenario, the ball is fired into a wormhole at an angle such that, if it continues along that path, it will exit the wormhole in the past at just the right angle to collide with its earlier self, thereby knocking it off course and preventing it from entering the wormhole in the first place. Thorne dubbed this problem "Polchinski's paradox" in 1994.[7] Later students of the whimsical problem came up with solutions which managed to avoid any inconsistencies, by having the ball emerge from the future at a different angle than the one used to generate the paradox, and deliver its younger self a glancing blow instead of knocking it completely away from the wormhole, a blow which changes its trajectory in just the right way so that it will travel back in time with the angle required to deliver its younger self this glancing blow.[7]
https://en.wikipedia.org/wiki/Joseph_Polchinski
A letter from the Chancellor of the Unioversity of California, Santa Barbara:
February 2, 2018
Dear Members of our Campus Community,
I am deeply saddened to share with you the news that Professor Emeritus Joseph
Polchinski passed away this morning, at home with his beloved wife, Professor Dorothy
Chun. I had the honor of visiting with Joe and Dorothy on January 21 and expressing
our enduring gratitude for Joe’s leadership, collegiality, and monumental contributions to
our campus and the global scientific community.
Dr. Polchinski joined our Physics faculty in 1992. He was a permanent member of our
Kavli Institute for Theoretical Physics and the Pat and Joe Yzurdiaga Professor of
Theoretical Physics. Prior to joining UC Santa Barbara, he was on the faculty at the
Univ
ersity of Texas at Austin, and served as a research associate at the Stanford Linear
Accelerator Center (SLAC) and at Harvard. He received his B.S. in Physics from
Caltech and his Ph.D. in Physics from UC Berkeley. He became professor emeritus in
March 2017, but continued to visit campus, attend lectures, and talk with colleagues.
His memoir, Memories of a Theoretical Physicist, was published last year.
Professor Polchinski was a brilliant and original thinker, renowned for his discovery of
D-branes, extended structures that appear to be central to the mathematics and physics
of string theory, and most recently for his advancement of the black hole firewall
hypothesis. He was the author of a widely used text on string theory, published by
Cambridge University Press. Early career recognitions, including a Hertz FoundationGraduate Fellowship, a National Science Foundation Postdoctoral Fellowship, and an Alfred P. Sloan Fellowship, were followed by numerous honors for his leading
contributions to fundamental physics. He was a Fellow of the American Physical Society
and the American Association for the Advancement of Science, and a member of the
National Academy of Sciences and the American Academy of Arts and Sciences. He
was awarded the Dannie Heineman Prize for Mathematical Physics from the American
Physical Society in 2007, the Dirac Medal of the International Center for Theoretical
Physics in 2008, and the Physics Frontiers Prizes in 2013 and 2014. Just last year, he
was awarded the 2017 Breakthrough Prize in Fundamental Physics, a $3-
million prize shared with two other physicists, “for transformative advances in quantum field theory, string theory, and quantum gravity.”
Joe was known for climbing mountains, both intellectual and literal. Many of our
colleagues fondly remember epic bike rides with him to the top of Gibraltar and Old San
Marcos Pass, discussing life and physics all the way. He set his sights high and navigated fearlessly over all obstacles in order to achieve the extraordinary, encouraging and inspiring others along the way.
His research has had a profound and lasting impact on our understanding of the universe. Throughout his career, he demonstrated tremendous creativity and insight not only in discovering new scientific truths, but also in communicating these complex ideas in a highly accessible and thought-provoking way. I still vividly remember his lively Faculty Research Lecture in 2014 on “Space-Time Versus the Quantum.” Through his bold ideas, unique insights, and rigorous pursuit of the deepest and most challenging questions, he left an indelible mark on all who were fortunate enough to learn from him and collaborate with him.
Professor Polchinski will be dearly missed by our entire UC Santa Barbara family. Our hearts and thoughts go out to Dorothy and their sons, Steven and Daniel, and to all of Joe’s family, friends, and colleagues around the world. Our campus flag will be lowered
in his honor.
Sincerely,
Henry T. Yang
Chancellor
https://chancellor.ucsb.edu/memos/?2.2.2...Polchinski
Joseph Polchinski (May 16, 1954 – February 2, 2018) was an American theoretical physicist and string theorist.[2][3]
Polchinski graduated from Canyon del Oro High School in Tucson, Arizona in 1971, obtained his B.S. degree from Caltech in 1975, and his Ph.D. from the University of California, Berkeley in 1980 under the supervision of Stanley Mandelstam. After postdoctoral positions at SLAC (1980–82) and Harvard (1982–84) he was professor at the University of Texas at Austin from 1984 to 1992. Since 1992 he has been professor in the Physics Department of the University of California, Santa Barbara and a permanent member of the Kavli Institute for Theoretical Physics there.[4]
Polchinski wrote the two-volume textbook String Theory, published in 1998. Among his many contributions to theoretical physics, D-branes are the best known. In 2008 he won the Dirac Medal for his work in superstring theory.[5] He won the 2017 Fundamental Physics Prize.[6]
In an unpublished communication to Kip Thorne circa 1990, commenting on the Novikov self-consistency principle (in relation to sending objects or people through a traversable wormhole into the past, and the time paradoxes that could result), Polchinski raised a potentially paradoxical situation involving a billiard ball sent through a wormhole which sends it back in time. In this scenario, the ball is fired into a wormhole at an angle such that, if it continues along that path, it will exit the wormhole in the past at just the right angle to collide with its earlier self, thereby knocking it off course and preventing it from entering the wormhole in the first place. Thorne dubbed this problem "Polchinski's paradox" in 1994.[7] Later students of the whimsical problem came up with solutions which managed to avoid any inconsistencies, by having the ball emerge from the future at a different angle than the one used to generate the paradox, and deliver its younger self a glancing blow instead of knocking it completely away from the wormhole, a blow which changes its trajectory in just the right way so that it will travel back in time with the angle required to deliver its younger self this glancing blow.[7]
In an unpublished communication to Kip Thorne circa 1990, commenting on the Novikov self-consistency principle (in relation to sending objects or people through a traversable wormhole into the past, and the time paradoxes that could result), Polchinski raised a potentially paradoxical situation involving a billiard ball sent through a wormhole which sends it back in time. In this scenario, the ball is fired into a wormhole at an angle such that, if it continues along that path, it will exit the wormhole in the past at just the right angle to collide with its earlier self, thereby knocking it off course and preventing it from entering the wormhole in the first place. Thorne dubbed this problem "Polchinski's paradox" in 1994.[7] Later students of the whimsical problem came up with solutions which managed to avoid any inconsistencies, by having the ball emerge from the future at a different angle than the one used to generate the paradox, and deliver its younger self a glancing blow instead of knocking it completely away from the wormhole, a blow which changes its trajectory in just the right way so that it will travel back in time with the angle required to deliver its younger self this glancing blow.[7]
https://en.wikipedia.org/wiki/Joseph_Polchinski
A letter from the Chancellor of the Unioversity of California, Santa Barbara:
February 2, 2018
Dear Members of our Campus Community,
I am deeply saddened to share with you the news that Professor Emeritus Joseph
Polchinski passed away this morning, at home with his beloved wife, Professor Dorothy
Chun. I had the honor of visiting with Joe and Dorothy on January 21 and expressing
our enduring gratitude for Joe’s leadership, collegiality, and monumental contributions to
our campus and the global scientific community.
Dr. Polchinski joined our Physics faculty in 1992. He was a permanent member of our
Kavli Institute for Theoretical Physics and the Pat and Joe Yzurdiaga Professor of
Theoretical Physics. Prior to joining UC Santa Barbara, he was on the faculty at the
Univ
ersity of Texas at Austin, and served as a research associate at the Stanford Linear
Accelerator Center (SLAC) and at Harvard. He received his B.S. in Physics from
Caltech and his Ph.D. in Physics from UC Berkeley. He became professor emeritus in
March 2017, but continued to visit campus, attend lectures, and talk with colleagues.
His memoir, Memories of a Theoretical Physicist, was published last year.
Professor Polchinski was a brilliant and original thinker, renowned for his discovery of
D-branes, extended structures that appear to be central to the mathematics and physics
of string theory, and most recently for his advancement of the black hole firewall
hypothesis. He was the author of a widely used text on string theory, published by
Cambridge University Press. Early career recognitions, including a Hertz FoundationGraduate Fellowship, a National Science Foundation Postdoctoral Fellowship, and an Alfred P. Sloan Fellowship, were followed by numerous honors for his leading
contributions to fundamental physics. He was a Fellow of the American Physical Society
and the American Association for the Advancement of Science, and a member of the
National Academy of Sciences and the American Academy of Arts and Sciences. He
was awarded the Dannie Heineman Prize for Mathematical Physics from the American
Physical Society in 2007, the Dirac Medal of the International Center for Theoretical
Physics in 2008, and the Physics Frontiers Prizes in 2013 and 2014. Just last year, he
was awarded the 2017 Breakthrough Prize in Fundamental Physics, a $3-
million prize shared with two other physicists, “for transformative advances in quantum field theory, string theory, and quantum gravity.”
Joe was known for climbing mountains, both intellectual and literal. Many of our
colleagues fondly remember epic bike rides with him to the top of Gibraltar and Old San
Marcos Pass, discussing life and physics all the way. He set his sights high and navigated fearlessly over all obstacles in order to achieve the extraordinary, encouraging and inspiring others along the way.
His research has had a profound and lasting impact on our understanding of the universe. Throughout his career, he demonstrated tremendous creativity and insight not only in discovering new scientific truths, but also in communicating these complex ideas in a highly accessible and thought-provoking way. I still vividly remember his lively Faculty Research Lecture in 2014 on “Space-Time Versus the Quantum.” Through his bold ideas, unique insights, and rigorous pursuit of the deepest and most challenging questions, he left an indelible mark on all who were fortunate enough to learn from him and collaborate with him.
Professor Polchinski will be dearly missed by our entire UC Santa Barbara family. Our hearts and thoughts go out to Dorothy and their sons, Steven and Daniel, and to all of Joe’s family, friends, and colleagues around the world. Our campus flag will be lowered
in his honor.
Sincerely,
Henry T. Yang
Chancellor
https://chancellor.ucsb.edu/memos/?2.2.2...Polchinski
The ideal subject of totalitarian rule is not the convinced Nazi or the dedicated Communist but instead the people for whom the distinction between fact and fiction, true and false, no longer exists -- Hannah Arendt.