The cosmological constant problem arises at the intersection between general relativity and quantum field theory, and is regarded as a fundamental problem in modern physics. In this paper we describe the historical and conceptual origin of the cosmological constant problem which is intimately connected to the vacuum concept in quantum field theory. We critically discuss how the problem rests on the notion of physically real vacuum energy, and which relations between general relativity and quantum field theory are assumed in order (...) to make the problem well-defined. (shrink)

The cosmological constant problem arises at the intersection between general relativity and quantum field theory, and is regarded as a fundamental problem in modern physics. In this paper we describe the historical and conceptual origin of the cosmological constant problem which is intimately connected to the vacuum concept in quantum field theory. We critically discuss how the problem rests on the notion of physically real vacuum energy, and which relations between general relativity and quantum field theory are assumed in order (...) to make the problem well-defined. (shrink)

our universe has a radius no smaller than 40 billion light- years—there's no sign, yet, of any edge to the universe. Though this is one piece of evidence for an infinite universe, it is not what really makes physicists think that the universe is ...

The mysteries of consciousness have gripped the human imagination for over 2,500 years. At the dawn of the new millennium, Understanding Consciousness provides new solutions to some of the deepest puzzles surrounding its nature and function. Drawing on recent scientific discoveries, Max Velmans challenges conventional reductionist thought, providing an understanding of how consciousness relates to the brain and physical world that is neither dualist, nor reductionist. Understanding Consciousness will be of great interest to psychologists, philosophers, neuroscientists and other professionals concerned (...) with mind/body relationships, and all who care deeply about this subject. (shrink)

Nature Network Groups hosted an invited workshop on 'Theories of Consciousness' during the second semester of 2009. There were presentations by each of 15 authors active in the field, followed by debate with other presenters and invitees. A week was allocated to each of the theories proposed; general discussion threads were also opened from time to time, as seemed appropriate. We offer here an account of the principal outcomes. It can be regarded as a contemporary, 'state of the art' snapshot (...) of thinking in this field. (shrink)

The cosmological constant problem arises at the intersection between general relativity and quantum field theory, and is regarded as a fundamental problem in modern physics. In this paper, we describe the historical and conceptual origin of the cosmological constant problem which is intimately connected to the vacuum concept in quantum field theory. We critically discuss how the problem rests on the notion of physically real vacuum energy, and which relations between general relativity and quantum field theory are assumed in order (...) to make the problem well-defined. (shrink)