Quantum Computing Stack Exchange
Quantum Computing Stack Exchange

Questions tagged [interpretations]

For questions about interpretations of quantum mechanics, e.g. Copenhagen, many-worlds, etc.

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Effects of quantum computing on parallel universes

I have heard a few times that one way of describing quantum computers is that they essentially use the computing power of their counterparts in alternate realities that they access through superposition. My first question is, of course, is this…
Snowshard
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Simulating a system inside a system

The minimum size of a computer that could simulate the universe would be the universe itself. This is quite a pretty big theory in classical computing and physics because to contain the information of the whole universe, you require a minimum…
Yuzuriha Inori
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What are tentpole topics in quantum computing?

Lots of beginners are starting to learn quantum computing. But there are also experienced people that have been working in this field for many years. What are some topics that might be considered important for a beginner to learn thoroughly? By…
user27286
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Does Planck's constant have any role in quantum computing?

I am new to the area of quantum computing, but as I study it I can't help wonder about the role of the Planck's constant. When one studies quantum mechanics one often finds statements that quantum mechanics reduces to classical physics if Planck's…
QC-Novice
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How can quantum interference happen in real world if a wave function does not have any physical meaning?

I understood quantum interference as a heart of quantum computing, because it enables two possibilities to cancel each other. Quantum algorithms utilize this property to reduce the probability of returning wrong answers and thus give higher chance…
suhdonghwi
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Does a classical computer really require $2^n$ complex numbers to represent the state of $n$ qubit quantum computer?

One often reads that the key reason why classical computers (probabilistic or deterministic) are unable to simulate quantum algorithms such as Simon's or Shor's efficiently is that a classical computer needs $2^n$ complex numbers to represent an $n$…
QC-Novice
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Many-Worlds Interpretation and GHZ States

I'm working through a problem set, and I've come across the following problem: In this problem, you'll explore something that we said in class about the Many-Worlds Interpretation of quantum mechanics: namely, that "two branches interfere with each…
Joe
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What is the "sum-over-paths" picture of quantum computing?

In chapter 9 of Scott Aaronson's book Quantum Computing Since Democritus (see online progenitor lecture notes here), he introduces a strange (to me) conceptualization of applying two Hadamard-like operations to a qbit, summed up in this diagram: I…
ahelwer
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With only one qubit, where does the bomb tester get its improvement over what's achievable classically?

The Elitzur-Vaidman [EV] bomb tester, first described in 1993, is a wonderful "pre-Shor's algorithm" application of quantum information. The original paper is written in the language of Mach-Zhender interferometers, beam splitters, detectors, and…
Mark Spinelli
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How similar is the recent (2021) tardigrade experiment to a Schrödinger's cat experiment?

In a recent paper on the arXiv, a team of researchers from Singapore and elsewhere claim to have established entanglement between a superconducting qubit and a tardigrade (or water-bear), which is a teeny little critter that's known for being able…
Mark Spinelli
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Does the Copenhagen interpretation (+ "quasi-classical measuring apparatus") allow one to bypass a derivation's objection?

Background I previously asked this question, in which I'm trying to better understand this joshphysics's derivation of an interpretation of the time-energy uncertainty principle. And the gist of what I get is (from the answers and the chatroom)…
More Anonymous
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Interpretation of a circuit that yields the same result for initializations $|+\rangle$ and $|-\rangle$

How can I interpret a quantum circuit that results in the same state for the initialization $\newcommand{\ket}[1]{|#1\rangle}\newcommand{\bra}[1]{\langle #1|}\ket{+}$ and $\ket{-}$? For example, the circuit consisting of a CNOT where the control…
upe
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Interpretations of quantum computing power

Over the years I encountered different explanations of quantum computing advantage over classical computers. But I am not sure which explanations are in fact valid and which are not. Quantum computer utilizes parallelism. It tries to arrive to the…
Anixx
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Do the Heisenberg uncertainty principle and quantum decoherence relate in some way?

Up until now I assumed (in simple words) that a qubit collapses because of the heisenberg uncertainty principle, meaning that we can not measure a qubit without changing it state. But now I've read about the concept of quantum decoherence that…
Blubsiwubsi
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In $|x_1,...,x_n\rangle$, can the individual constituents be called qubits?

A qubit is a quantum system in which the Boolean states 0 and 1 are rep- resented by a prescribed pair of normalised and mutually orthogonal quantum states labeled as ${|0⟩, |1⟩}$ According to [1]. Then a quantum register $\mid…
gen
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