Lecture 6 | Quantum Entanglements, Part 1 (Stanford)

Lecture 6 of Leonard Susskind's course concentrating on Quantum Entanglements (Part 1, Fall 2006). Recorded October 30, 2006 at Stanford University.

This Stanford Continuing Studies course is the first of a three-quarter sequence of classes exploring the "quantum entanglements" in modern theoretical physics. Leonard Susskind is the Felix Bloch Professor of Physics at Stanford University.

Complete playlist for the course:
http://www.youtube.com/view_play_list?p=A27CEA1B8B27EB67

Stanford Continuing Studies: http://continuingstudies.stanford.edu/

About Leonard Susskind: http://www.stanford.edu/dept/physics/people/faculty/sussk...

Stanford University channel on YouTube:
http://www.youtube.com/stanford

Category:

Education

Tags:

• Science
• physics
• math
• theory
• relativity
• equation
• formula
• Leonard
• Susskind

[0101483]

Answer: the coefficients are not normalized.

[0101483]

In the 2 slit electron experiment, with unobserved paths, starting from point 0 on the left then to points +/-1, then to the symmetric midpoint 0 on the screen, say the normalized psi coefficients of the two paths are both equal to 1/sqrt(2). The probability of any given electron being found at the midpoint when either slit is open (but not both) is then 1/2. With both slits open, the probability of finding the electron at the midpoint would then be 2. What is wrong here?

[MuggsMcGinnis]

@MuggsMcGinnis At minute 36, the camera-person does it exactly right. Letting Susskind step into and out of the field while displaying clearly the entire contents of the white board.

[MuggsMcGinnis]

@zeperf88 A given electron might be observed in different ways. You measure the spin of an electron with a magnetic field. The field orientation will always be observed to be either in alignment or opposition (anti-alignment) to the imposed magnetic field. If a beam of electrons are polarized to be perpendicular to the field, 1/2 will be observed to be aligned with the field (no photon) & 1/2 pointed the other way (photon emission).

[MuggsMcGinnis]

Advice to the camera-person: It's less important to keep the speaker centered than it is to show what they are talking about. When he points to an equation, focus on the equation, even if only his hand remains in the frame. It's not like videoing a dance, you're helping people take notes.

[grunder20]

I am gonna work on this. GOOD VIDEO!!

[agapitoflores001]

I cannot relate much to this one. I can't say anything. But anyway thanks for the video.

[setnorm]

How wonderful it is to be able to see what he's writing again! (Unlike lecture 5).

[TheGuyWhoToldMeToTel]

@rmgorichanaz It's the same dude in every lecture. I loved the one where he argued for 15 minutes in general relativity on whether or not you could buy a 1 farad capacitor (which had nothing to do with what Susskind was talking about). Asking questions is one thing, but if I were his classmate, I'd lock him out of the classroom.

[PLecN]

@guillefix The eigenvalues are the possible values that could be measured. If the spin of an electron is measured, the result of the measurement will be +1, or -1. Also, you could have more than one eigenvector associated with a particular eigenvalue, so number of eigenvalues does not equal dim of space of states.

[zeperf88]

Does anyone understand the Bell Inequality thing? How can the first electron be up at zero degrees and also down at 45 degrees? He said the second electron is positive 45 because the first is negative 45.