Macroscopic quantum Definition and 14 Threads

Does gravity cause quantum decoherence? In the microscopic world, gravity seems to act weakly, but in the macroscopic world, it seems to act strongly. Is this the boundary between the microscopic world and the macroscopic world? So a phenomenon like quantum tunneling can occur in the microscopic...

Very confused about this article and the experiment it's based on. I'm not very knowledgeable on this, but I'm very confused on what's happening here. It seems extremely weird to me

Summary: What did Omnès mean with this? I found an old article by Roland Omnès which analyzes the EPR paradox and offers a solution to it (https://www.sciencedirect.com/science/article/abs/pii/0375960189900182). At some point, the article says: "Some macroscopic systems do not satisfy the...

In a discussion between Sam Harris and Brian Greene, at this point, Brian stated that even if we return the brain and all the environment to its previous state, we "WON'T MAKE THE SAME NOISES"; I know that for example, indeterminacy in determining the precise time of decay of an atom (and the...

This thread is to serve as both a compilation and ground of discussion of key experiments, both historical and planned, which attempt to probe possible macroscopic limits of QM, taking into account e.g. some particular gravitational/optical/mechanical/superconducting/etc aspect and/or...

Steven Weinberg has lately been critical of QM. He now also has a technical paper out called 'Lindblad Decoherence in Atomic Clocks', available on arxiv. Here is the abstract: It's a short paper (6 pgs of text), arguing for objective collapse (a la GRW/Diosi-Penrose/etc) instead of...

Max Tegmark in his paper “Many worlds in context” http://arxiv.org/abs/0905.2182 Argues that …. .“Everett’s MWI is simply standard QM with the collapse postulate removed, so that the Schrödinger equation holds without exception”. He also argues that from this we can deduce that not only...

I am aware and well read on the decoherence approach to understanding how conglomerations of micro quantum systems will tend to lose quantum coherence via interaction with the environment. The cross terms in the density matrix for the system will tend to zero (due to the partial trace...

Has anyone performed experiments regarding macroscopic quantum coherence (superposition of and macroscopic object)? What about testing if macroscopic objects obey macrorealism, or whether QM prevails? Links to articles or experiments would be apprecited.

My first thread here. Please bear with my lack of knowledge. I talked to a physics grad student about whether it's fair to describe QM as a theory applied only to microscopic objects. Although the definition of "fair" is ambiguous, at least he told me that, from his understanding, he wouldn't...

I read often that the transition from quantum to classical, the fact that there normally no macroscopic quantum objects are observed, has only become clear with the proper understanding of the decoherence mechanism. But what about Broglie wavelength!? Physicists knew before, that macroscopic...

In some discussions here about quantum effects in the macro world, ZapperZ will only admit that things like superconductivity, Bose Einstein condensates etc. are good examples. But these are just macroscpic quantum coherent phenomena. Of course, if you have a flux qubit, you can directly...

I have heard many times that's quantum mechanics doesn't apply at the macroscopic level. But I am not sure if I fully understood what was meant. Surely quantum mechanics applies even to macroscopic objects, its just that the wavefunction of such objects is so highly localized that we in effect...

[SOLVED] Macroscopic quantum model Hi! I'm supposed to calculate the quantum number of a macroscopic system (The Earth and a satellite). I should assume that the satellite is moving in a circular motion around earth, and that it fulfills the same quantization conditions as the Bohr model...