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Frasi di Lee Smolin

Lee Smolin è un fisico teorico statunitense che ha dato notevoli contributi alla teoria quantistica della gravitazione e, in particolare, alla gravità quantistica a loop. Wikipedia  

✵ 6. Giugno 1955
Lee Smolin photo
Lee Smolin: 52   frasi 0   Mi piace

Lee Smolin: Frasi in inglese

“Combine general relativity and quantum theory into a single theory that can claim to be the complete theory of nature. This is called the problem of quantum gravity.”

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Lee Smolin

The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next (2007)

“Neither space nor time has any existence outside the system of evolving relationships that comprises the universe. Physicists refer to this feature of general relativity as background independence.”

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Lee Smolin libro Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

“The positive energy theorem was for half a century or more an open challenge to relativists. Many attempts were made to prove flat spacetime was stable, but none completely succeeded completely until a majestic tour de force of geometric reasoning of Shoen and Yau. This was followed two years later by a proof of Witten, which was as elegant as it was short. It is this proof of Witten’s that we take as a template here for the quantum theory.”

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Lee Smolin

"Positive energy in quantum gravity" arXiv (Jun 10, 2014)

“I… propose that time and its passage are fundamental and real and the hopes and beliefs about timeless truths and timeless realms are mythology.”

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Lee Smolin

Time Reborn: From the Crisis in Physics to the Future of the Universe (2013)

“Quantum theory can be described as a new kind of language to be used in a dialogue between us and the systems we study with our instruments. …It tells us nothing about what the world would be like in our absence.”

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Lee Smolin

The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next (2007)

“Calculation establishes that a quantum positive energy theorem may be possible using a representation based on the Ashtekar connection. Left open is a key question of whether this use of the Ashtekar connection is necessary or whether a positive quantum energy result can be achieved for representations based on other connections, i. e., for [other] values of the Immirzi parameter.”

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Lee Smolin

"Positive energy in quantum gravity" arXiv (Jun 10, 2014)

“Jacob Bekenstein found… in 1971 that every black hole must have an entropy proportional to the area of its horizon… Stephen Hawking then refined this by showing that the constant of proportionality must be… exactly one quarter. …entropy is supposed to correspond to a measure of information …Loop quantum gravity… [gives] a detailed description of the microscopic structure of a black hole. …a horizon can have, for each quantized unit of area, a finite number of states. Counting them, we get exactly Bekenstein's result…”

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Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

“Some of the effects predicted by the theory [of loop quantum gravity] appear to be in conflict with one of the principles of Einstein's special theory of relativity… that the speed of light is a universal constant. …Photons of higher energy travel slightly slower than low-energy photons. …the principle of [general] relativity is preserved but Einstein's special theory of relativity requires modification. …A photon can have an energy-dependent speed without violating the principle of [general] relativity!”

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Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

“The hypothesis underlying all approaches to the landscape is that there is a cosmological setting in which different regions or epochs of the universe can have different effective laws. This implies the existence of spacetime regions not directly observable… These regions must either be in the past of our big bang, or far enough away from us to be causally unrelated.”

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Lee Smolin

"A perspective on the landscape problem" arXiv (Feb 15, 2012)

“If we believe that the task of physics is the discovery of a timeless mathematical equation that captures every aspect of the universe, then we believe that the truth about the universe lies outside the universe.”

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Lee Smolin

Time Reborn: From the Crisis in Physics to the Future of the Universe (2013)

“Many of the founders of quantum mechanics, including Einstein, Erwin Schrödinger, and Louis de Broglie… were realists. For them quantum theory… was not a complete theory, because it did not provide a picture of reality absent our interaction with it. On the other side were Niels Bohr, Werner Heisenberg, and many others. Rather than being appalled, they embraced this new way of doing science.”

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Lee Smolin

The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next (2007)

“Time is described only in terms of change in the network of relationships that describes space.”

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Lee Smolin libro Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

“The landscape problem represents a serious problem in the development of science. Its solution requires… the construction of speculative cosmological scenarios, which posit regions or epochs of our universe for which we presently have no observable evidence. Nonetheless we must insist on taking seriously only scenarios and hypotheses that make falsifiable or strongly verifiable predictions, otherwise people can just make stuff up and the distinction between science and mythology becomes porous. …there are already candidate solutions that make real, falsifiable predictions.”

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Lee Smolin

"A perspective on the landscape problem" arXiv (Feb 15, 2012)

“We are the result of processes much more complicated than the small aspects of our lives and societies over which we have some control.”

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Lee Smolin libro Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

“To be human is to be suspended between danger and opportunity. …The challenge of life is to choose wisely, from the enormous number of possible dangers, what's worth worrying about. It is also about choosing, from all the opportunities… always in the face of incomplete knowledge of the consequences.”

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Lee Smolin

Time Reborn: From the Crisis in Physics to the Future of the Universe (2013)

“It is absurd in general relativity to speak of a universe in which nothing happens.”

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Lee Smolin libro Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

“There are unfortunately not a few good professional physicists who still think about the world as if space and time had an absolute meaning.”

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Lee Smolin libro Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

“There is nothing beyond the world except what we see, no background to it except its particular history.”

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Lee Smolin libro Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

“There is no fixed, eternal frame to the universe to define what may or may not exist.”

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Lee Smolin libro Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

“We detect light and particles that have traveled billions of light years on their way across the universe to us. During the billions of years of travel, very small effects due to quantum gravity can be amplified to the point that we can detect them.”

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Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

“The relational picture of space and time has implications that are as radical as those of natural selection, not only for science but for our perspective on who we are and how we came to exist in this evolving universe of relations.”

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Lee Smolin libro Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

“Relativity and… quantum… remain incomplete…. the main reason each is incomplete is the existence of the other. The mind calls for a third theory to unify all of physics, and for a simple reason. Nature is… "unified." …interconnected, in that everything interacts with everything else.”

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Lee Smolin

The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next (2007)

“Spacetime… turns out to be discrete, described by a structure called spin foam.”

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Lee Smolin

"Loop Quantum Gravity," The New Humanists: Science at the Edge (2003)

“We have known since the middle of the nineteenth century that the world is not composed only of particles. …the world is also composed of fields. …General relativity is a theory of… the gravitational field. …Because there are three sets of field lines, the gravitational field defines a network of relationships having to do with how the… lines link with one another. …This is why we call relativity a relational theory.”

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Lee Smolin libro Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

“The first principle of cosmology must be 'There is nothing outside the universe'. This is not to exclude religion or mysticism… But if it is knowledge that we desire… we need to seek answers to questions about the things we can see… only things that exist in the universe.”

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Lee Smolin libro Three Roads to Quantum Gravity

Three Roads to Quantum Gravity (2000)

“One of the evident facts about the world is the stability of empty space-time. In classical general relativity we can explain this as a consequence of the positive energy theorem… the positive energy theorem must extend in some suitable form to any viable quantum theory of gravity.”

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Lee Smolin

"Positive energy in quantum gravity" arXiv (Jun 10, 2014)

“Thinking in time is not relativism but a form of relationalism… the truest description of something consists of specifying its relationships to other parts of the system it is part of.”

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Lee Smolin

Time Reborn: From the Crisis in Physics to the Future of the Universe (2013)

“The landscape problem and the problem of background independence are closely linked. The latter is the only route the former has to experimental confirmation.”

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Lee Smolin

"A perspective on the landscape problem" arXiv (Feb 15, 2012)

“Having begun my life in science searching for the equation beyond time, I now believe that the deepest secret of the universe is that its essence rests in how it unfolds moment by moment in time.”

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Lee Smolin

Time Reborn: From the Crisis in Physics to the Future of the Universe (2013)

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