Quantum computing
A quantum computer consists of a number of qubits, each one in suspension between the possible values 1 or 0, ready to fall into one or the other of these values, but subject to a network of interactions that impose conditions. A simple such condition for two qubits could be that the outcome has to be either (1,0) or (0,1). The problem to be solved by the quantum computer is couched in the form of a set of relations that must all be satisfied at decision time. In this it resembles the game sudoku, where also the solution has to conform to a set of rules. The classical analog of this, performed on an ordinary computer, could be to sequentially go through all possible bit strings, testing all the conditions on each one of them, until a string is found that simultaneously fulfills them all. If the quantum computer has 100 qubits, the classical computer would have to hunt in the worst case through 2100 bit strings, of which there is an outrageously large number, before finding the correct one, whereas the quantum computer falls, under the influence of the simultaneously acting condition-interactions, in one fell swoop into a solving bit configuration!
Perception
After every cut in a movie, your eyes are hit by a novel scene. It usually takes your mind less than a second to build up a representation of that scene. In order to do so it has to answer tons of questions, questions that are constrained, but not answered at all, by the pictures. So, you pretty immediately get the gist of the scene, the kind of situation, you recognize objects and persons, get their spatial arrangement, the action they are engaged in and so on. A typical question concerns the distance the objects are from you. The movie screen is flat, so that the pictures contain no direct hint at those distances. And still, in a flash of a second you get them along with all the rest! How does the brain do that?
Perception as Quantum Computing
As the pictures leave the depth dimension and the answers to so many other questions wide open, the brain responds by activating, for each question, a whole range of neurons, each of which standing for one possible hypothesis or answer to the question. This superposition is left, for the tiniest of moments, floating in suspension. But this suspension quickly collapses, leaving in each set of alternative hypotheses only one active. This collapse is shaped by vast arrays of interactions that put conditions on which hypotheses are compatible and can be simultaneously true. So, given the apparent size of the object in the picture, the true size of an object and its distance have to conform to a fixed relation. According to this rule alone, both size and distance are still left open, but not independently of each other, just as our two qubits in the quantum computer, and more conditions are needed to settle that question. All the interactions, all the conditions between hypotheses, are acting simultaneously in the brain, and while the vast superposition of alternative hypothesis is collapsing –this collapse being the process analogous to reading out results in the quantum computer– the set of all the hypotheses that support each other by the compatibility conditions stays active, answering all those questions and forming a representation of the scene.
The nature of the interactions
What is the nature of the interactions between qubits in the quantum computer and between the hypotheses in the brain? In the quantum world, physicists have no clear answer to this question and bashfully speak of entanglement, as if the restrictions on simultaneously realizable quantum measurements or qubit values fell from heaven. Einstein spoke of spooky action at a distance. In the brain, however, where hypotheses are represented by active neurons, those interactions are mediated by hundreds of trillions of neural fibers. The read-out process of the quantum computer, the spontaneous collapse of the ambiguously floating superposition of qubit states, which corresponds to the quantum-mechanical measurement process, is treated by physicists equally as a mystery, with a clear description of before and after, while whoever attempts to discuss the transition itself is considered a crank.
Consciousness
Not that neuroscientists don’t cherish their own mystery, kept away from the light of day in the Temple’s Holy of Holies, while in reality it is the light of day itself, our inner reality: consciousness. The consciousness results from none other than the collapse of ambiguity of our neural quantum computer to states of conformity of all hypotheses with each other and the sensory input in terms of learnt rules of interaction.
It is curious to note that there is quite a literature on consciousness being ultimately responsible for the quantum mechanical measurement process, and another set of proposals to explain consciousness as result of quantum effects, but these are just attempts by the two fields to shroud own obscurity by a conundrum of the other. It may be much more fruitful to map out in detail this analogy between quantum computing and conscious perception to help illuminating each field’s own dark corner by insights from the other.
Quantum computing
A quantum computer consists of a number of qubits, each one in suspension between the possible values 1 or 0, ready to fall into one or the other of these values, but subject to a network of interactions that impose conditions. A simple such condition for two qubits could be that the outcome has to be either (1,0) or (0,1). The problem to be solved by the quantum computer is couched in the form of a set of relations that must all be satisfied at decision time. In this it resembles the game sudoku, where also the solution has to conform to a set of rules. The classical analog of this, performed on an ordinary computer, could be to sequentially go through all possible bit strings, testing all the conditions on each one of them, until a string is found that simultaneously fulfills them all. If the quantum computer has 100 qubits, the classical computer would have to hunt in the worst case through 2100 bit strings, of which there is an outrageously large number, before finding the correct one, whereas the quantum computer falls, under the influence of the simultaneously acting condition-interactions, in one fell swoop into a solving bit configuration!
Perception
After every cut in a movie, your eyes are hit by a novel scene. It usually takes your mind less than a second to build up a representation of that scene. In order to do so it has to answer tons of questions, questions that are constrained, but not answered at all, by the pictures. So, you pretty immediately get the gist of the scene, the kind of situation, you recognize objects and persons, get their spatial arrangement, the action they are engaged in and so on. A typical question concerns the distance the objects are from you. The movie screen is flat, so that the pictures contain no direct hint at those distances. And still, in a flash of a second you get them along with all the rest! How does the brain do that?
Perception as Quantum Computing
As the pictures leave the depth dimension and the answers to so many other questions wide open, the brain responds by activating, for each question, a whole range of neurons, each of which standing for one possible hypothesis or answer to the question. This superposition is left, for the tiniest of moments, floating in suspension. But this suspension quickly collapses, leaving in each set of alternative hypotheses only one active. This collapse is shaped by vast arrays of interactions that put conditions on which hypotheses are compatible and can be simultaneously true. So, given the apparent size of the object in the picture, the true size of an object and its distance have to conform to a fixed relation. According to this rule alone, both size and distance are still left open, but not independently of each other, just as our two qubits in the quantum computer, and more conditions are needed to settle that question. All the interactions, all the conditions between hypotheses, are acting simultaneously in the brain, and while the vast superposition of alternative hypothesis is collapsing –this collapse being the process analogous to reading out results in the quantum computer– the set of all the hypotheses that support each other by the compatibility conditions stays active, answering all those questions and forming a representation of the scene.
The nature of the interactions
What is the nature of the interactions between qubits in the quantum computer and between the hypotheses in the brain? In the quantum world, physicists have no clear answer to this question and bashfully speak of entanglement, as if the restrictions on simultaneously realizable quantum measurements or qubit values fell from heaven. Einstein spoke of spooky action at a distance. In the brain, however, where hypotheses are represented by active neurons, those interactions are mediated by hundreds of trillions of neural fibers. The read-out process of the quantum computer, the spontaneous collapse of the ambiguously floating superposition of qubit states, which corresponds to the quantum-mechanical measurement process, is treated by physicists equally as a mystery, with a clear description of before and after, while whoever attempts to discuss the transition itself is considered a crank.
Consciousness
Not that neuroscientists don’t cherish their own mystery, kept away from the light of day in the Temple’s Holy of Holies, while in reality it is the light of day itself, our inner reality: consciousness. The consciousness results from none other than the collapse of ambiguity of our neural quantum computer to states of conformity of all hypotheses with each other and the sensory input in terms of learnt rules of interaction.
It is curious to note that there is quite a literature on consciousness being ultimately responsible for the quantum mechanical measurement process, and another set of proposals to explain consciousness as result of quantum effects, but these are just attempts by the two fields to shroud own obscurity by a conundrum of the other. It may be much more fruitful to map out in detail this analogy between quantum computing and conscious perception to help illuminating each field’s own dark corner by insights from the other.