Artur Ekert - Academia.edu (original) (raw)
Papers by Artur Ekert
CRC Press eBooks, Nov 14, 2005
Physics World, Sep 1, 2009
ABSTRACT Bell's inequality makes a seemingly insane scenario possible --- devices of unkn... more ABSTRACT Bell's inequality makes a seemingly insane scenario possible --- devices of unknown or dubious provenance, even those that are manufactured by our enemies, can be safely used for secret communication. And this is for real! All that is needed to implement such a bizarre form of cryptography is a loophole-free violation of Bell's inequalities. It is on the edge of being technologically feasible. I will provide a brief overview of quantum and post-quantum cryptography and describe how studies of entanglement and the foundations of quantum theory influenced the way we may soon protect information.
Acta Physica Polonica A, 1998
Journal of Modern Optics, Dec 1, 1994
arXiv (Cornell University), Aug 25, 2006
arXiv (Cornell University), Oct 24, 2004
... R. Lupacchini); L. Fortnow, Separating classes; B. Hart, The uncountable spectra of countable... more ... R. Lupacchini); L. Fortnow, Separating classes; B. Hart, The uncountable spectra of countable theories; G. Hjorth, Vaught conjecture on analytic sets; T. Jech, Stationary sets; C. Jockusch, Ramsey's theorem, computability, and second-order number theory; L. Lipshitz, The model ...
The classical theory of computation usually does not refer to physics. Pioneers such as Turing, C... more The classical theory of computation usually does not refer to physics. Pioneers such as Turing, Church, Post, and G��del managed to capture the correct classical theory by intuition alone and, as a result, it is often falsely assumed that its foundations are self-evident and purely abstract. They are not!
Physics World, Oct 1, 1989
Quantisation of the electromagnetic field leads us simplistically to think of the field as fluctu... more Quantisation of the electromagnetic field leads us simplistically to think of the field as fluctuating around some average value that could be predicted by a classical theory, whereas all statistical properties of the fluctuations must be derived from a quantum theory. The character of the fluctuations depends on the quantum state of the field. Even in a vacuum, where the average value of the field is zero, its mean square value due to fluctuations is positive. This quantum noise associated with these fluctuations is inherent and cannot be removed no matter how carefully we get rid of various environmental disturbances and fluctuations. But even though the quantum noise is here to stay, we can still control and manipulate it.
arXiv (Cornell University), Jun 30, 2022
第１章 量子情報の物理：基本概念 第２章 量子暗号 第３章 量子稠密符号化と量子テレポーテーション 第４章 量子計算の概念 第５章 量子計算の実現に向けた最先端の実験 第６章 量子ネットワークと... more 第１章 量子情報の物理：基本概念 第２章 量子暗号 第３章 量子稠密符号化と量子テレポーテーション 第４章 量子計算の概念 第５章 量子計算の実現に向けた最先端の実験 第６章 量子ネットワークと多粒子エンタングルメント 第７章 デコヒーレンスと量子エラー訂正 第８章 エンタングルメント精製
A computation is a physical process. It may be performed by a piece of electronics or on an abacu... more A computation is a physical process. It may be performed by a piece of electronics or on an abacus, or in your brain, but it is a process that takes place in nature and as such it is subject to the laws of physics. Quantum computers are machines that rely on characteristically quantum phenomena, such as quantum interference and quantum entanglement in order to perform computation. In this series of lectures I want to elaborate on the computational power of such machines. 1 Physical Representation of Information Suppose you have n physical objects and each object has k distinguishable states. If you can access each object separately and put it into any of the k states then with very little effort you can prepare any of the N = k different configurations of the combined systems. Let us put k = 2 and refer to each object of this type as a physical bit. We label the two states of a physical bit as 0 and 1. Any collection of n physical bits can be prepared in N = 2 different configuratio...
Philosophical Transactions of the Royal Society A, 1998
Nature Physics, 2018
Device-independent quantum cryptography promises unprecedented security, but it is regarded as a ... more Device-independent quantum cryptography promises unprecedented security, but it is regarded as a theorist's dream and an experimentalist's nightmare. A new mathematical tool has now pushed its experimental demonstration much closer to reality.
Progress in Quantum Electronics, 2017
50 Years of Science in Singapore, 2016
CRC Press eBooks, Nov 14, 2005
Physics World, Sep 1, 2009
ABSTRACT Bell's inequality makes a seemingly insane scenario possible --- devices of unkn... more ABSTRACT Bell's inequality makes a seemingly insane scenario possible --- devices of unknown or dubious provenance, even those that are manufactured by our enemies, can be safely used for secret communication. And this is for real! All that is needed to implement such a bizarre form of cryptography is a loophole-free violation of Bell's inequalities. It is on the edge of being technologically feasible. I will provide a brief overview of quantum and post-quantum cryptography and describe how studies of entanglement and the foundations of quantum theory influenced the way we may soon protect information.
Acta Physica Polonica A, 1998
Journal of Modern Optics, Dec 1, 1994
arXiv (Cornell University), Aug 25, 2006
arXiv (Cornell University), Oct 24, 2004
... R. Lupacchini); L. Fortnow, Separating classes; B. Hart, The uncountable spectra of countable... more ... R. Lupacchini); L. Fortnow, Separating classes; B. Hart, The uncountable spectra of countable theories; G. Hjorth, Vaught conjecture on analytic sets; T. Jech, Stationary sets; C. Jockusch, Ramsey's theorem, computability, and second-order number theory; L. Lipshitz, The model ...
The classical theory of computation usually does not refer to physics. Pioneers such as Turing, C... more The classical theory of computation usually does not refer to physics. Pioneers such as Turing, Church, Post, and G��del managed to capture the correct classical theory by intuition alone and, as a result, it is often falsely assumed that its foundations are self-evident and purely abstract. They are not!
Physics World, Oct 1, 1989
Quantisation of the electromagnetic field leads us simplistically to think of the field as fluctu... more Quantisation of the electromagnetic field leads us simplistically to think of the field as fluctuating around some average value that could be predicted by a classical theory, whereas all statistical properties of the fluctuations must be derived from a quantum theory. The character of the fluctuations depends on the quantum state of the field. Even in a vacuum, where the average value of the field is zero, its mean square value due to fluctuations is positive. This quantum noise associated with these fluctuations is inherent and cannot be removed no matter how carefully we get rid of various environmental disturbances and fluctuations. But even though the quantum noise is here to stay, we can still control and manipulate it.
arXiv (Cornell University), Jun 30, 2022
第１章 量子情報の物理：基本概念 第２章 量子暗号 第３章 量子稠密符号化と量子テレポーテーション 第４章 量子計算の概念 第５章 量子計算の実現に向けた最先端の実験 第６章 量子ネットワークと... more 第１章 量子情報の物理：基本概念 第２章 量子暗号 第３章 量子稠密符号化と量子テレポーテーション 第４章 量子計算の概念 第５章 量子計算の実現に向けた最先端の実験 第６章 量子ネットワークと多粒子エンタングルメント 第７章 デコヒーレンスと量子エラー訂正 第８章 エンタングルメント精製
A computation is a physical process. It may be performed by a piece of electronics or on an abacu... more A computation is a physical process. It may be performed by a piece of electronics or on an abacus, or in your brain, but it is a process that takes place in nature and as such it is subject to the laws of physics. Quantum computers are machines that rely on characteristically quantum phenomena, such as quantum interference and quantum entanglement in order to perform computation. In this series of lectures I want to elaborate on the computational power of such machines. 1 Physical Representation of Information Suppose you have n physical objects and each object has k distinguishable states. If you can access each object separately and put it into any of the k states then with very little effort you can prepare any of the N = k different configurations of the combined systems. Let us put k = 2 and refer to each object of this type as a physical bit. We label the two states of a physical bit as 0 and 1. Any collection of n physical bits can be prepared in N = 2 different configuratio...
Philosophical Transactions of the Royal Society A, 1998
Nature Physics, 2018
Device-independent quantum cryptography promises unprecedented security, but it is regarded as a ... more Device-independent quantum cryptography promises unprecedented security, but it is regarded as a theorist's dream and an experimentalist's nightmare. A new mathematical tool has now pushed its experimental demonstration much closer to reality.
Progress in Quantum Electronics, 2017
50 Years of Science in Singapore, 2016