215 reputation
17
bio website thisquantumworld.com
location Pondicherry, India
age 64
visits member for 3 years, 6 months
seen Mar 30 '13 at 11:12

Born and raised in Ger­many, Ulrich Mohrhoff joined the Sri Aurobindo Inter­na­tional Centre of Edu­ca­tion (SAICE), Pondicherry (India), as an under­grad­uate stu­dent in 1972.

From 1974 to 1978 he studied physics at the Uni­ver­sity of Göt­tingen, Ger­many, and at the Indian Insti­tute of Sci­ence in Ban­ga­lore (India). Since his set­tling in Pondicherry in 1978 he pur­sues inde­pen­dent research in the foun­da­tions of physics and at the inter­face of physics and Indian philosophy/​psychology. In 1996 he began pub­lishing orig­inal research in var­ious peer-​​reviewed jour­nals (see his pub­li­ca­tions and pre­sen­ta­tions).

Since 2000 he teaches a philo­soph­i­cally ori­ented course of con­tem­po­rary physics, which is offered to higher sec­ondary and under­grad­uate stu­dents at the SAICE. His text­book (The World According to Quantum Mechanics: Why the Laws of Physics Make Perfect Sense After All, published by World Scientific and due to be released shortly), is based largely on the mate­rial he devel­oped for this course. He maintains two blogs, This Quantum World and An Aurobindonian in Quantumland.


Jun
25
awarded  Yearling
Feb
19
answered Another question about energy(Improved)
Feb
19
answered Could quantum mechanics work without the Born rule?
Apr
5
comment In quantum mechanics, why do the probabilities of the possible outcomes of a measurement add up to 1?
the outcomes isn't whatever "comes out." It's what is represented by a projector. My question is not: does QM "always predict missing probability of detection" but: can QM predict with certainty that a measurement will have one of its possible outcomes (which are represented by orthogonal projectors on an HS)?
Apr
4
comment Does quantum mechanics allow us to formulate causally sufficient conditions for the occurrence of an outcome?
I don't think "no outcome" is the same as a "null outcome." In the first case, all possible outcomes are represented by projectors, and none of them corresponds to the failure of the apparatus to indicate an outcome. In the second case, the failure of the apparatus to respond in any way is one of the possible outcomes and is therefore represented by a projector. In this case every measurement does indeed have an outcome. But this brings up yet another question, which I may ask in another thread...
Apr
4
comment Does quantum mechanics allow us to formulate causally sufficient conditions for the occurrence of an outcome?
True, @Luboš those things are computable. Using cross sections and coupling constants, one should in principle be able to calculate the efficiency of any detector. Since this is always less than one, the answer to the title question is negative.
Apr
4
comment Does quantum mechanics allow us to formulate causally sufficient conditions for the occurrence of an outcome?
Agreed. I take this to imply a negative answer to the title question.
Apr
4
comment In quantum mechanics, why do the probabilities of the possible outcomes of a measurement add up to 1?
Perhaps it is best to focus on a position measurement using an array of detectors. To simplify further, just two detectors and a state assigning to them a total probability of 1. Since no detector is perfect, no every one of these measurements will have an outcome. All Bohr would require in this case that the unsuccessful measurements be discarded or ignored, if we want to compare the predicted probabilities with the measured ones.
Apr
3
revised In quantum mechanics, why do the probabilities of the possible outcomes of a measurement add up to 1?
Follow-up question posted separately.
Apr
3
comment Does quantum mechanics allow us to formulate causally sufficient conditions for the occurrence of an outcome?
@Anna, Zero particle is an outcome only if one is using a perfect (100% efficient) detector. But such a detector does not exist. See my previous comment.
Apr
3
comment Does quantum mechanics allow us to formulate causally sufficient conditions for the occurrence of an outcome?
@Anna, one needs to distinguish two cases. (i) If a 100% efficient detector doesn't detect a particle, there is no particle. (ii) If a real-world detector (which never is 100% efficient) fails to detect a particle, there may or may not be a particle. One could mock up a 100% efficient detector by ignoring all instances in which it failed to work, but this would beg the question.
Apr
3
revised Does quantum mechanics allow us to formulate causally sufficient conditions for the occurrence of an outcome?
clarified (paragraph added from question which the present question is following up)
Apr
3
comment In quantum mechanics, why do the probabilities of the possible outcomes of a measurement add up to 1?
@user2898, one needs to distinguish two cases. (i) If a 100% efficient detector doesn't detect a particle, there is no particle. (ii) If a real-world detector (which never is 100% efficient) fails to detect a particle, there may or may not be a particle. You could mock up a 100% efficient detector by ignoring all instances in which it failed to work, but this would beg the question.
Apr
3
comment In quantum mechanics, why do the probabilities of the possible outcomes of a measurement add up to 1?
@Mark, as you suggested, I have posted the follow-up question separately.
Apr
3
asked Does quantum mechanics allow us to formulate causally sufficient conditions for the occurrence of an outcome?
Apr
3
comment In quantum mechanics, why do the probabilities of the possible outcomes of a measurement add up to 1?
@sigoldberg1, a successful measurement has an outcome. An attempted measurement may or may not be successful. An unsuccessful measurement has no outcome.
Apr
3
revised In quantum mechanics, why do the probabilities of the possible outcomes of a measurement add up to 1?
corrected wording in last paragraph
Apr
3
revised In quantum mechanics, why do the probabilities of the possible outcomes of a measurement add up to 1?
Made the question more specific in response to inadequate answers.
Apr
2
awarded  Student
Apr
2
asked In quantum mechanics, why do the probabilities of the possible outcomes of a measurement add up to 1?