Entries by Mark Stuckey

Superdeterminism and the Mermin Device

Superdeterminism as a way to resolve the mystery of quantum entanglement is generally not taken seriously in the foundations community, as explained in this video by Sabine Hossenfelder (posted in Dec 2021). In her video, she argues that superdeterminism should be taken seriously, indeed it is what quantum mechanics (QM) is screaming for us to…

How Quantum Information Theorists Revealed the Relativity Principle at the Foundation of Quantum Mechanics

This Insight is a condensed version of No Preferred Reference Frame at the Foundation of Quantum Mechanics. Reference numbers here correspond to that paper. This Insight is an expanded version of Quantum information theorists produce new ‘understanding’ of quantum mechanics. Feynman famously said, “I think I can safely say that nobody understands quantum mechanics” [1]. Despite…

Dark Energy Part 2: LCDM Cosmology

This is Part 2 of a 3-part series explaining evidence for so-called “dark energy” leading to a current positive cosmological acceleration. The evidence comes from fitting the SCP Union2.1 type Ia supernova data which indicates the existence of a cosmological constant ##\Lambda## (read “Lambda”, thus ##\Lambda##CDM is sometimes written LCDM) in Einstein’s equations (EEs) of…

Dark Energy Part 1: Einstein-deSitter Cosmology

In this 3-part series, I want to motivate the (re)introduction of the cosmological constant ##\Lambda## into Einstein’s equations of general relativity (GR) per the Supernova Cosmology Project (SCP) Union2.1 type Ia supernova data. As you probably know, this discovery won Perlmutter, Schmitt, and Riess the 2011 Nobel Prize in Physics “for the discovery of the accelerating…

Answering Mermin’s Challenge with the Relativity Principle

Note: This Insight was previously titled, “Answering Mermin’s Challenge with Wilczek’s Challenge.” While that version of this Insight did not involve any particular interpretation of quantum mechanics, it did involve the block universe interpretation of special relativity. I have updated this Insight to remove the block universe interpretation, so that it now answers Mermin’s challenge…

Exploring Bell States and Conservation of Spin Angular Momentum

In a recent thread, I outlined how to compute the correlation function for the Bell basis states \begin{equation}\begin{split}|\psi_-\rangle &= \frac{|ud\rangle \,- |du\rangle}{\sqrt{2}}\\ |\psi_+\rangle &= \frac{|ud\rangle + |du\rangle}{\sqrt{2}}\\ |\phi_-\rangle &= \frac{|uu\rangle \,- |dd\rangle}{\sqrt{2}}\\ |\phi_+\rangle &= \frac{|uu\rangle + |dd\rangle}{\sqrt{2}} \end{split}\label{BellStates}\end{equation} when they represent spin states. The first state ##|\psi_-\rangle## is called the “spin singlet state” and it…

The Quantum Mystery of Wigner’s Friend

In this Insight I will introduce the quantum mystery called “Wigner’s friend” using Healey’s version [1] of Frauchiger and Renner’s (FR’s) version [2] of Wigner’s version [3]. As with much of physics, the explication becomes more succinct and comprehensible with each successive rendering. I will show how this mystery results from treating classical information (behaving…

The Unreasonable Effectiveness of the Popescu-Rohrlich Correlations

In this Insight, I will show how the Popescu-Rohrlich (superquantum) correlations provide an unreasonable advantage in a particular “quantum guessing game” using a pedagogical counterpart from the book “Totally Random: Why Nobody Understands Quantum Mechanics” by Tanya Bub and Jeffrey Bub (Princeton University Press, 2018). As I showed in my Insight Why the Quantum, the PR correlations violate…

The Schwarzschild Metric: A Newtonian Comparison

A Short Proof of Birkoff’s Theorem derived the Schwarzschild metric in units of ##G = c = 1##: \begin{equation} ds^2 = -\left(1 – \frac{2M}{r}\right)dt^2 + \left(1 – \frac{2M}{r}\right)^{-1}dr^2 + r^2d\theta^2 + r^2 \sin^2\theta d\phi^2   \label{metric} \end{equation} and I used that metric in The Schwarzschild Metric: Part 1, GPS Satellites to show that Global Positioning System (GPS) clocks…

The Schwarzschild Metric: The Photon Sphere

  A Short Proof of Birkoff’s Theorem derived the Schwarzschild metric in units of ##G = c = 1##: \begin{equation} ds^2 = -\left(1 – \frac{2M}{r}\right)dt^2 + \left(1 – \frac{2M}{r}\right)^{-1}dr^2 + r^2d\theta^2 + r^2 \sin^2\theta d\phi^2   \label{metric} \end{equation} and I used that metric in The Schwarzschild Metric: Part 1, GPS Satellites to show that Global Positioning System (GPS)…

The Schwarzschild Metric: GPS Satellites

  A Global Positioning System (GPS) device gives your precise location by receiving light pulses from satellites with synchronized clocks then triangulating your location based on that information [1]. Since light travels at 300 million meters per second, your location will be off by about 1 meter if the clock times are off by only…

Understanding Retrocausality and Blockworld

In an Insights series “Blockworld and its Foundational Implications,” I quoted Huw Price and Ken Wharton in several places advocating a blockworld approach to physics (called the Lagrangian Schema[1]). While Ken did sign off on my use of these quotes, I wasn’t entirely fair to the Price & Wharton program because I didn’t reveal their…

Blockworld and Its Foundational Implications: Time Dilation and Length Contraction

  This is the first in a 5-part series of Insights that will introduce blockworld (aka “block universe”) and use it to address a puzzle (origin of the universe), paradoxes[1] (of closed timelike curves), and conundrums[2] (of quantum nonlocality) that I have seen discussed on Physics Forums. Blockworld (BW) says the past, present and future are equally ‘real’, i.e.,…

Weak Values Part 2: The Quantum Cheshire Cat Experiment

In a previous Insight, Weak Values Part 1: “Asking Photons Where They Have Been,” I showed different methods for computing the relative intensities in the weak measurements done by Danan, Farfurnik, Bar-Ad, and Vaidman (DFBV)[1]. In that experiment, DFBV had a weak transverse signal, created by mirrors oscillating with small amplitudes transverse to the beam path through an interferometer, piggyback…

Weak Values Part 1: Asking Photons Where They Have Been

In a previous Insight on retrocausality, I explained an experiment by Danan, Farfurnik, Bar-Ad, and Vaidman (DFBV)[1], “Asking Photons Where They Have Been” using various retrocausal models. In this Insight, I will give a brief introduction to the formalism for computing the relative power spectra in that experiment. Specifically, I will show how the weak…

Learn About the Greenberger-Horne-Zeilinger Experiment

In two previous Insights, I shared Mermin’s explanation of the Hardy experiment[1] and the Mermin device[2]. Both of his corresponding AJP papers presented nontechnical arguments against “instruction sets” aka “counterfactual definiteness” for quantum mechanics (QM). In the case of the Mermin device, Elitzur & Dolev showed a particular experimental instantiation yielded a quantum counterpart to the liar paradox[3]. Herein I will share a third Mermin AJP paper[4]…

The Quantum Liar Experiment: An Instantiation of the Mermin Device

In 1981, Mermin published a paper[1], “Bringing home the atomic world: Quantum mysteries for anybody” in which he explained the mystery of quantum nonlocality[2] without requiring the formalism of quantum mechanics (QM). I will summarize that argument then show how the QM formalism fits his results and how his device is instantiated in Elitzur & Dolev’s quantum liar experiment (QLE)[3]. The quantum state…