Thoughts about quantum computing and the wave function

Qubit bloch sphere

The main difference between a quantum computer and a classical one is the qubit. Qubits are like classical bits, in that they hold binary values of either 1 or 0, on or off, true or false, etc. However, qubits, being quantum objects, can be in a superposition of both states at once. The physical manifestation … Continue reading Thoughts about quantum computing and the wave function

David Deutsch’s version of many worlds

Schrodinger's cat in many worlds

I've written about the bizarre nature of quantum physics many times, providing a lightning primer back in May on three major interpretations: Copenhagen, pilot-wave, and many worlds.  The many worlds interpretation (MWI) is often summarily dismissed by people, often along with visceral shudders or high doses of outrage.  I understand the discomfort.  When I first … Continue reading David Deutsch’s version of many worlds

The measurement problem, Copenhagen, pilot-wave, and many worlds

With quantum physics, we have a situation where a quantum object, such as a photon, electron, atom or similar scale entity, acts like a wave, spreading out in a superposition, until we look at it (by measuring it in some manner), then it behaves like a particle.  This is known as the measurement problem. Now, … Continue reading The measurement problem, Copenhagen, pilot-wave, and many worlds

Is entanglement decoherence from the outside, and decoherence entanglement from the inside?

A recent tweet by Sean Carroll has me thinking. https://twitter.com/seanmcarroll/status/1204128666273271808 Quantum decoherence is said to occur when a particular quantum system becomes entangled with its environment, that is to say, as information about the quantum system spreads throughout the environment, that system undergoes at least an apparent wave function collapse.  It stops behaving like a … Continue reading Is entanglement decoherence from the outside, and decoherence entanglement from the inside?

Sean Carroll’s Something Deeply Hidden

I'm just about finished reading Sean Carroll's Something Deeply Hidden.  I was going to wait to post this until I'd completely finished, but all I've got left is the appendix, I perceive that I've gotten through the main points, and discussion on the previous post is veering in this direction. As widely reported, Carroll is … Continue reading Sean Carroll’s Something Deeply Hidden

Why you can’t use quantum entanglement for faster than light communication

Albert Einstein, with his theory of special relativity, established that the speed of light is the absolute speed limit of the universe.  A rocket ship attempting to accelerate to the speed of light encounters some well known effects: time dilation, mass increase, and length contraction.  The closer to the speed of light it gets, the … Continue reading Why you can’t use quantum entanglement for faster than light communication

Sean Carroll on the Many Worlds Interpretation of quantum mechanics

Related to the post last week on quantum mechanics, here is a talk that got mentioned in the discussion thread.  Warning: Carroll is a passionate advocate for the Many Worlds Interpretation, so don't expect a fair and balanced discussion.  The video is about an  hour long. http://www.youtube.com/watch?v=iXRLDatmbgA A couple of points.  Carroll notes that we … Continue reading Sean Carroll on the Many Worlds Interpretation of quantum mechanics

Do all quantum trails inevitably lead to Everett?

I've been thinking lately about quantum physics, a topic that seems to attract all sorts of crazy speculation and intense controversy, which seems inevitable.  Quantum mechanics challenges our deepest held most cherished beliefs about how reality works.  If you study the quantum world and you don't come away deeply unsettled, then you simply haven't properly … Continue reading Do all quantum trails inevitably lead to Everett?