Amsterdam University Press eBooks

1 An introduction to the quantum world

Koen Groenland

Published Mar 9, 2025• 0 citations

Abstract

An introduction to the quantum worldAt a glance you don't need to understand quantum mechanics to understand the functionality of quantum computers.But if you insist, quantum mechanics describes the behaviour of the smallest particles.It leads to many counterintuitive phenomena: computer memory can store multiple pieces of data simultaneously, but, when measured, nature selects just a single piece and throws away all the others.

DOI: 10.1515/9789048568994-002

Related papers

An introduction to the quantum world

Koen Groenland

You don’t need to understand quantum mechanics to understand the functionality of quantum computers. But if you insist, quantum mechanics describes the behaviour of the smallest particles. It leads to many counter-intuitive phenomena: computer memory can store multiple pieces of data simultaneously, but, when measured, nature selects just a single piece and throws away all the others.

Routledge eBooksOct 1, 20250 citations

Quantum Mechanics

Andrew Rex

Quantum mechanics (or simply quantum physics) is the branch of physics that applies to particles and systems of particles, such as atoms and molecules. In that realm the laws of classical mechanics and classical electromagnetism break down, and only quantum mechanics provides the concepts and computational methods that explain observed phenomena. Quantum mechanics uses specially developed tools, such as wave functions, that contain all of the relevant information about particles and systems. is approach is needed to understand the true nature of electromagnetic radiation and how that radiation interacts with matter. e mathematics used in quantum mechanics is highly specialized and often complex. In this chapter we’ll address some of the key questions that require quantum mechanics without presenting the full mathematical formalism. e important questions we’ll address all deal with observable physical phenomena. We’ll discuss how quantum mechanics is used to answer these questions but will omit the advanced mathematical details.

CRC Press eBooksFeb 12, 20140 citations

A Pragmatist Understanding of Quantum Mechanics

Richard Healey

Applications of quantum mechanics have led to many successful predictions and explanations of puzzling phenomena, and we now apply quantum mechanics to gain, process, and communicate information in novel ways. We can understand quantum mechanics by understanding how we have applied it. We should not seek agreement on the nature of the world it represents, because this theory does not itself represent the physical world (though its applications do help us to represent it better). When applied to a quantum state, quantum mechanics yields probabiities for physical events: both state and probability are objective--not because they represent elements of phyiscal reality, but because each exerts norrmative authority over the beliefs of anyone who accepts quantum mechanics and applies it relative to a physical situation they may (but need not) occupy. These events may be described by statements that are meaningful in an appropriate environmental context, and quantum mechanics can help one to say when that is. Measurement creates an appropriate context, so here the Born rule indirectly yields probabilities of measurement outcomes. The quantum state of a system does not "collapse" on measurement: a new state must be assigned relative to a physical situation in which information about the outcome is accessible. Understood this way, there is no measurement problem, and violations of Bell inequalities does not demonstrate "spooky" non-local action. Quantum field theories have no physical ontology of their own: a quantum field is a mathematical object in a model whose application helps us to improve and extend our descriptions of the world in other terms. We cannot realise the scenario of Wigner's friend and its recent extensions: but the data that provide overwhelming evidence for quantum mechanics are objective in the same sense as the relative measurement outcomes described in those scenarios.

quant-pharXiv:2604.02197Apr 3, 20260 citations

Introducing Quantum Mechanics

Steven M. Pascal

Because atoms and molecules are small, their behavior can only be understood using quantum mechanics, rather than classical mechanics. Quantum mechanics amounts to studying the behavior of electrons and nuclei and their interactions. We will limit ourselves to slowly moving electrons and nuclei, and thus will not need to discuss relativistic quantum mechanics. Large particles also obey quantum mechanics, but the relevant wavelengths are so small that we don't notice them. Small particles absolutely require the use of quantum mechanics for any meaningful understanding. This treatment is not merely an inconvenience: it leads to useful and interesting phenomena such as the Pauli exclusion principle, the Aufbau principle, Hund's rules, the Heisenberg uncertainty principle, wave-particle duality, the photoelectric effect, Ehrenfest's theorem, and the correspondence principle.

CRC Press eBooksJul 12, 20232 citations

A Pragmatist Understanding of Quantum Mechanics

Richard Healey

Applications of quantum mechanics have led to many successful predictions and explanations of puzzling phenomena, and we now apply quantum mechanics to gain, process, and communicate information in novel ways. We can understand quantum mechanics by understanding how we have applied it. We should not seek agreement on the nature of the world it represents, because this theory does not itself represent the physical world (though its applications do help us to represent it better). When applied to a quantum state, quantum mechanics yields probabilities for physical events: both state and probability are objective—not because they represent elements of physical reality, but because each exerts normative authority over the beliefs of anyone who accepts quantum mechanics and applies it relative to a physical situation they may (but need not) occupy. These events may be described by statements (about values of magnitudes) that are meaningful in an appropriate environmental context, and quantum mechanics can help one to say when that is. Measurement creates an appropriate context, so here the Born rule indirectly yields probabilities of measurement outcomes. The quantum state of a system does not “collapse” on measurement: a new state must be assigned relative to a physical situation in which information about the outcome is accessible. Understood this way, there is no measurement problem, and violation of Bell inequalities does not demonstrate “spooky” non-local action. Quantum field theories have no physical ontology of their own: a quantum field is a mathematical object in a model whose application helps to improve and extend our descriptions of the world in other terms. We cannot realise the scenario of Wigner’s friend and its recent extensions: but the data that provide overwhelming evidence for quantum mechanics are objective in the same sense as the relative measurement outcomes described in those scenarios.

Dec 1, 20250 citations

The Rollicking World of Quantum Mechanics

Robert Ciesla

Deepening one's knowledge on quantum mechanics and related physics paves the way for a greater understanding of the definite future of computing and cryptography. Quantum mechanics is a branch of physics focusing on the smallest scales known to us: the atomic and the sub-atomic realms. It has numerous implications for our world, as discussed in the previous chapter, and it comes with some controversy as well. We'll now go more or less clavicle deep into this sub-atomic level and explore its numerous paradigm-shifting phenomena.

Apress eBooksJan 1, 20200 citations