Papers by Muhammad Ali Shahbaz
In this paper, I have argued that quantum gravity is unitary and information is preserved in blac... more In this paper, I have argued that quantum gravity is unitary and information is preserved in black hole formation and evaporation. I assume the evolution is given by a Euclidean path integral over metrics of all topologies. The integral over topologically trivial metrics can be done by dividing the time interval into thin slices and using a linear interpolation to the metric in each slice. The integral over each slice will be unitary and so the whole path integral will be unitary.
On the other hand, the path integral over topologically non trivial metrics will lose information and will be asymptotically
independent of its initial conditions. Thus the total path integral will be unitary and quantum mechanics is safe.
A black hole should behave in accordance with conventional quantum mechanics, implying a unitary ... more A black hole should behave in accordance with conventional quantum mechanics, implying a unitary evolution, one is forced to believe that local quantum field theory near the black hole horizon is very different from what had hitherto been accepted. This would give us very valuable information
concerning physics in the Planck length region, notably a mathematical structure very close to that of super string theory, but it does lead to conceptual difficulties.
In the classical theory black holes can only absorb and not emit particles. However it is shown t... more In the classical theory black holes can only absorb and not emit particles. However it is shown that quantum mechanical effects cause black holes to create and emit particles as if they were hot bodies with temperature!
The first paper in which the concept of Hawking Radiation was introduced!
In these lectures Roger Penrose and I will put forward our related but rather different viewpoint... more In these lectures Roger Penrose and I will put forward our related but rather different viewpoints on the nature of space and time. We shall speak alternately and shall give three
lectures each, followed by a discussion on our different approaches. I should emphasize that these will be technical lectures. We shall assume a basic knowledge of general relativity and quantum theory.
This is the original paper by Oppenheimer and Snyder (1939) in which they show how a continued gr... more This is the original paper by Oppenheimer and Snyder (1939) in which they show how a continued gravitational contraction gave rise to black hole!
ʺWhen should a theory be ranked as scientific?ʺ or ʺIs there a criterion for the scientific chara... more ʺWhen should a theory be ranked as scientific?ʺ or ʺIs there a criterion for the scientific character or status of a theory?ʺ
Science and philosophy have a very long history, dating back at least to the 16th and 17th centur... more Science and philosophy have a very long history, dating back at least to the 16th and 17th centuries, when the first scientist-philosophers, such as Bacon, Galilei, and Newton, were beginning the process of turning natural philosophy into science. Contemporary relationships between the two fields are still to some extent marked by the distrust that maintains the divide between the so-called “two cultures.” An increasing number of philosophers, however, are making conceptual contributions to sciences ranging from quantum mechanics to evolutionary biology, and a few scientists are conducting research relevant to classically philosophical fields of inquiry, such as consciousness and moral decision-making. This article will introduce readers to the borderlands between science and philosophy,
beginning with a brief description of what philosophy of science is about, and including a discussion of how the two disciplines can fruitfully interact not only at the level of scholarship, but also when it
comes to controversies surrounding public understanding of science.
We argue that philosophical and historical research can constitute a “Biohumanities” that deepens... more We argue that philosophical and historical research can constitute a “Biohumanities” that deepens our understanding of biology itself, engages in constructive “science criticism,” helps formulate new “visions of biology,” and facilitates “critical science communication.” We illustrate these ideas with two recent “experimental philosophy” studies of the concept of the gene and of the concept of innateness
conducted by ourselves and collaborators. We conclude that the complex and often troubled relations between science and society are critical to both parties, and argue that the philosophy and history of
science can help to make this relationship work.
The book deals with the problems of philosophy and shows, as I
believe, that the method of formul... more The book deals with the problems of philosophy and shows, as I
believe, that the method of formulating these problems rests on the misunderstanding of the logic of our language. Its whole meaning could be summed up somewhat as follows: What can be said at all can be said clearly; and whereof one cannot speak thereof one must be silent.
The BICEP2 (CMB polarimeter) experiment has recently announced the discovery of inflationary grav... more The BICEP2 (CMB polarimeter) experiment has recently announced the discovery of inflationary gravitational waves in the B-mode power spectrum, with the tensor to scalar ratio r = 0:20. If con rmed, this provides a tremendous boost for a class of inflationary models in which the energy scale during inflation is on the order of 10 to power 16 GeV.
Inspired by this discovery, we provide an update on five relatively well motivated inflationary models in which the inflaton is a Standard Model singlet scalar field.
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Papers by Muhammad Ali Shahbaz
On the other hand, the path integral over topologically non trivial metrics will lose information and will be asymptotically
independent of its initial conditions. Thus the total path integral will be unitary and quantum mechanics is safe.
concerning physics in the Planck length region, notably a mathematical structure very close to that of super string theory, but it does lead to conceptual difficulties.
The first paper in which the concept of Hawking Radiation was introduced!
lectures each, followed by a discussion on our different approaches. I should emphasize that these will be technical lectures. We shall assume a basic knowledge of general relativity and quantum theory.
beginning with a brief description of what philosophy of science is about, and including a discussion of how the two disciplines can fruitfully interact not only at the level of scholarship, but also when it
comes to controversies surrounding public understanding of science.
conducted by ourselves and collaborators. We conclude that the complex and often troubled relations between science and society are critical to both parties, and argue that the philosophy and history of
science can help to make this relationship work.
believe, that the method of formulating these problems rests on the misunderstanding of the logic of our language. Its whole meaning could be summed up somewhat as follows: What can be said at all can be said clearly; and whereof one cannot speak thereof one must be silent.
Inspired by this discovery, we provide an update on five relatively well motivated inflationary models in which the inflaton is a Standard Model singlet scalar field.
On the other hand, the path integral over topologically non trivial metrics will lose information and will be asymptotically
independent of its initial conditions. Thus the total path integral will be unitary and quantum mechanics is safe.
concerning physics in the Planck length region, notably a mathematical structure very close to that of super string theory, but it does lead to conceptual difficulties.
The first paper in which the concept of Hawking Radiation was introduced!
lectures each, followed by a discussion on our different approaches. I should emphasize that these will be technical lectures. We shall assume a basic knowledge of general relativity and quantum theory.
beginning with a brief description of what philosophy of science is about, and including a discussion of how the two disciplines can fruitfully interact not only at the level of scholarship, but also when it
comes to controversies surrounding public understanding of science.
conducted by ourselves and collaborators. We conclude that the complex and often troubled relations between science and society are critical to both parties, and argue that the philosophy and history of
science can help to make this relationship work.
believe, that the method of formulating these problems rests on the misunderstanding of the logic of our language. Its whole meaning could be summed up somewhat as follows: What can be said at all can be said clearly; and whereof one cannot speak thereof one must be silent.
Inspired by this discovery, we provide an update on five relatively well motivated inflationary models in which the inflaton is a Standard Model singlet scalar field.