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Charles H. Bennett

Charles H. Bennett
IBM · IBM Research China

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149
Publications
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68,447
Citations

Publications

Publications (149)
Article
Full-text available
In their article, ‘That is not dead which can eternal lie: the aestivation hypothesis for resolving Fermi’s paradox’, Sandberg et al. try to explain the Fermi paradox (we see no aliens) by claiming that Landauer’s principle implies that a civilization can in principle perform far more (\({\sim } 10^{30}\) times more) irreversible logical operations...
Preprint
In their article, 'That is not dead which can eternal lie: the aestivation hypothesis for resolving Fermi's paradox', Sandberg et al. try to explain the Fermi paradox (we see no aliens) by claiming that Landauer's principle implies that a civilization can in principle perform far more (${\sim} 10^{30}$ times more) irreversible logical operations (e...
Conference Paper
Although written aboutfifteen years ago, Wiesner’s seminal paper, to which the origin of quantum cryptography must be traced back, did not appear in print until the spring of 1983 [W83]. The first published account of these ideas thus appeard in the proceedings of the second annual CRYPTO conference [BBBW83]. However, the concepts presented there w...
Article
Recently a great deal of attention has focused on quantum computation following a sequence of results [4, 16, 15] suggesting that quantum computers are more powerful than classical probabilistic computers. Following Shor's result that factoring and the extraction of discrete logarithms are both solvable in quantum polynomial time, it is natural to...
Conference Paper
We describe a protocol for quantum oblivious transfer , utilizing faint pulses of polarized light, by which one of two mutually distrustful parties ("Alice") transmits two one-bit messages in such a way that the other party ("Bob") can choose which message he gets but cannot obtain information about both messages (he will learn his chosen bit's val...
Article
An unknown quantum state jOEi can be disassembled into, then later reconstructed from, purely classical information and purely nonclassical EPR correlations. To do so the sender, "Alice," and the receiver, "Bob," must prearrange the sharing of an EPRcorrelated pair of particles. Alice makes a joint measurement on her EPR particle and the unknown qu...
Article
We describe results from an apparatus and protocol designed to implement quantum key distribution, by which two users, who share no secret information initially: 1) exchange a random quantum transmission, consisting of very faint flashes of polarized light; 2) by subsequent public discussion of the sent and received versions of this transmission es...
Conference Paper
The use of quantum mechanical systems, such as polarized photons, to record information gives rise to novel cryptographic phenomena, not achievable with classical recording media: 1) A Verify Only Memory (VOM) that, with high probability, cannot be read or copied by someone ignorant of its contents; 2) the multiplexing of two messages in such a way...
Article
Full-text available
When elementary quantum systems, such as polarized photons, are used to transmit digital information, the uncertainty principle gives rise to novel cryptographic phenomena unachievable with traditional transmission media, e.g. a communications channel on which it is impossible in principle to eavesdrop without a high probability of being detected....
Article
Dual to the usual noisy channel coding problem, where a noisy (classical or quantum) channel is used to simulate a noiseless one, reverse Shannon theorems concern the use of noiseless channels to simulate noisy ones, and more generally the use of one noisy channel to simulate another. For channels of nonzero capacity, this simulation is always poss...
Conference Paper
The information revolution is based on what a physicist would call a classical view of information. Quantum effects were long regarded as a mere nuisance for information processing, preventing information in microscopic objects from being observed or copied accurately, but are now known to make possible feats like quantum cryptography and possible...
Patent
Full-text available
A wearable video recording system with time-bracketed authentication is provided and includes a article, including a spine, wearable by a user, a recording device, supported on the spine, to generate a recording of a scene, an affecter subsystem, supported on the spine, to influence the scene being recorded with unpredictable data and an untrusted...
Article
We point out that arguments for the security of Kish's noise-based cryptographic protocol have relied on an unphysical no-wave limit, which if taken seriously would prevent any correlation from developing between the users. We introduce a noiseless version of the protocol, also having illusory security in the no-wave limit, to show that noise and t...
Article
Ekert has described a cryptographic scheme in which Einstein-Podolsky-Rosen (EPR) pairs of particles are used to generate identical random numbers in remote places, while Bell's theorem certifies that the particles have not been measured in transit by an eavesdropper. We describe a related but simpler EPR scheme and, without invoking Bell's theorem...
Article
Two separated observers, by applying local operations to a supply of not-too-impure entangled states ({\em e.g.} singlets shared through a noisy channel), can prepare a smaller number of entangled pairs of arbitrarily high purity ({\em e.g.} near-perfect singlets). These can then be used to faithfully teleport unknown quantum states from one observ...
Article
In this paper, we investigate how the use of a channel with perfect authenticity but no privacy can be used to repair the defects of a channel with imperfect privacy but no authenticity. More precisely, let us assume that Alice and Bob wish to agree on a secret random bit string, and have at their disposal an imperfect private channel and a perfect...
Article
Protocols such as quantum teleportation and measurement-based quantum computation highlight the importance of entanglement as a resource to be quantified and husbanded. Unlike classical shared randomness, entanglement has a profound effect on the capacity of quantum channels: a channel's entanglement-assisted capacity can be much greater than its u...
Article
We study the power of closed timelike curves (CTCs) and other nonlinear extensions of quantum mechanics for distinguishing nonorthogonal states and speeding up hard computations. If a CTC-assisted computer is presented with a labeled mixture of states to be distinguished--the most natural formulation--we show that the CTC is of no use. The apparent...
Article
In this talk, I discuss the mystery of the second law and its relation to quantum information. There are many explanations of the second law, mostly satisfactory and not mutually exclusive. Here, I advocate quantum mechanics and quantum information as something that, through entanglement, helps resolve the paradox or the puzzle of the origin of the...
Article
Full-text available
This article reports an open discussion that took place during the Keenan Symposium “Meeting the Entropy Challenge” (held in Cambridge, Massachusetts, on October 4, 2007) following the short presentations—each reported as a separate article in the present volume—by Adrian Bejan, Bjarne Andresen, Miguel Rubi, Signe Kjelstrup, David Jou, Miroslav Grm...
Conference Paper
The thermodynamics of computation is well understood for computing engines (rdquoBrownian computersrdquo) that are ideal in the sense that they can make forward and backward steps along the intended computation path, but not transitions to unrelated states. The thermodynamics of error-prone computations and error-correcting mechanisms is less well...
Article
A lot of research has been done on multipartite correlations. However, it seems strange that there is no definition of so called genuine multipartite correlations. In this paper we propose three reasonable postulates which each measure or indicator of genuine multipartite correlations (or genuine multipartite entanglement) should satisfy. We also i...
Article
An expanded theory of information transmission and processing has emerged over the past few years, encompassing the processing and transmission of intact quantum states, the interaction of quantum and classical information, the quantitative theory of entanglement, and the use of quantum information processing to speed up certain classical computati...
Article
We exhibit quantum channels whose classical and quantum capacities, when assisted by classical feedback, exceed their unassisted classical Holevo capacity. These channels are designed to be noisy in a way that can be corrected with the help of the output and a reference system entangled with part of the input. A similar construction yields quantum...
Article
Quantum-state tomography—the practice of estimating a quantum state by performing measurements on it—is useful in a variety of contexts. We introduce “gentle tomography” as a version of tomography that preserves the measured quantum data. As an application of gentle tomography, we describe a polynomial-time method for universal source coding.
Article
We review the goals of cryptography, explain how quantum laws allow some of these goals to be attained that could not be otherwise, and comment on the future of quantum cryptography and the nature of its security.
Article
The quantum principles of superposition and entanglement have led to a recasting of the foundations of information and computation theory, and are especially helpful in understanding the nature of privacy. The most private information, exemplified by a quantum eraser experiment, is best regarded as existing only conditionally and temporarily—after...
Article
Using a channel similar to one side of a Bell inequality experiment, we show how the auxiliary resources of shared sender:receiver entanglement and classical back communication, neither of which increases the forward capacity of any classical channel, can greatly increase both the quantum and classical capacities of some quantum channels. Joint wor...
Article
Remote state preparation is the variant of quantum state teleportation in which the sender knows the quantum state to be communicated. The original paper introducing teleportation established minimal requirements for classical communication and entanglement but the corresponding limits for remote state preparation have remained unknown until now: p...
Article
We survey progress in understanding quantum information in terms of equivalences, reducibilities, and asymptotically achievable rates for transformations among nonlocal resources such as classical communication, entanglement, and particular quantum states or channels. In some areas, eg source coding, there are straightforward parallels to classical...
Article
Full-text available
The book is now in its fifth printing. Note that the second, fourth and fifth printings contain corrections based on the errata below. The third printing does not contain any corrections beyond those in the second printing. First, Second, Third, Fourth & Fifth Printing (July, 2002) pp 4 On page 4, in the first full sentence on the page, there is a...
Article
Virtually all of today's information technology is based on the manipulation of classical bits. Quantum systems offer the potential of a much more powerful computing technology, however. In their Perspective, Bennett and Shor discuss an important aspect of quantum computing--the theoretical capacity of a quantum information channel. Although a numb...
Article
We describe a collection of techniques whereby audiovisual or other recordings of significant events can be made in a way that hinders falsification, pre-dating, or post-dating by interested parties, even by the makers and operators of the recording equipment. A central feature of these techniques is the interplay between private information, which...
Article
Landauer's principle, often regarded as the basic principle of the thermodynamics of information processing, holds that any logically irreversible manipulation of information, such as the erasure of a bit or the merging of two computation paths, must be accompanied by a corresponding entropy increase in non-information-bearing degrees of freedom of...
Article
We consider interactions as bidirectional channels. We investigate the capacities for interaction Hamiltonians and nonlocal unitary gates to generate entanglement and transmit classical information. We give analytic expressions for the entanglement generating capacity and entanglement-assisted one-way classical communication capacity of interaction...
Article
The article discusses the evolutionary histories of chain letters. A study of chain letters shows ways to infer the family tress of anything that evolves over time, from biological genomes to languages to plagiarized schoolwork. In the article, 33 versions of a chain letter are presented for analysis.
Article
Some mathematical and natural objects (a random sequence, a sequence of zeros, a perfect crystal, a gas) are intuitively trivial, while others (e.g. the human body, the digits of #) contain internal evidence of a nontrivial causal history.
Article
This edited transcript is a lively, informal presentation of quantum computation and quantum error correction by one of the founders and major contributors to the field.
Article
Full-text available
The entanglement-assisted classical capacity of a noisy quantum channel (CE) is the amount of information per channel use that can be sent over the channel in the limit of many uses of the channel, assuming that the sender and receiver have access to the resource of shared quantum entanglement, which may be used up by the communication protocol. We...
Article
While Kolmogorov complexity is the accepted absolute measure of information content in an individual finite object, a similarly absolute notion is needed for the information distance between two individual objects, for example, two pictures. We give several natural definitions of a universal information metric, based on length of shortest programs...
Article
Random beacons-information sources that broadcast a stream of random digits unknown by anyone beforehand-are useful for various cryptographic purposes. But such beacons can be easily and undetectably sabotaged, so that their output is known beforehand by a dishonest party, who can use this information to defeat the cryptographic protocols supposedl...
Article
We have made progress on many fronts on the understanding and characterization of entanglement. Various new forms of bound (i.e. undistillable) entanglement have been introduced, as part of our work on unextendable product states. Cases of "superactivation" of bound entanglement, in which two different bound entangled states, when joined, produce d...
Article
Quantum teleportation uses prior entanglement and forward classical communication to transmit one instance of an unknown quantum state. Remote state preparation (RSP) has the same goal, but the sender knows classically what state is to be transmitted. We show that the asymptotic classical communication cost of RSP is one bit per qubit--half that of...
Article
Full-text available
We consider the simulation of the dynamics of one nonlocal Hamiltonian by another, allowing arbitrary local resources but no entanglement nor classical communication. We characterize notions of simulation, and proceed to focus on deterministic simulation involving one copy of the system. More specifically, two otherwise isolated systems $A$ and $B$...
Article
found at our website [14]. No two letters are identical. In fact, most of them differ significantly. There are 15 different titles, 23 different names for "an office employee", 25 different names for the author of the article. Misspells, missing or added phrases, sentences and paragraphs, and swapped sentences are commonplace. The following table l...
Article
arises when one attempts to classify numbers as "interesting" or "dull": there can be no dull numbers, because, if there were, the first of them would be interesting on that account. Berry's paradox can be avoided and tamed by restricting nameability to mean describability as output of an algorithm or computer program. Consider the function C(x) =...
Article
In information processing, as in physics, our classical world view provides an incomplete approximation to an underlying quantum reality. Quantum effects like interference and entanglement play no direct role in conventional information processing, but they can—in principle now, but probably eventually in practice—be harnessed to break codes, creat...
Article
Cryptography, in its narrow meaning the art of secret communication, has always been the stuff of intrigue, of military campaigns and assassinations that succeed or fail depending on whether encrypted messages survive the scrutiny of eavesdroppers. Simon Singh's The Code Book, a popular history in the tradition of David Kahn's classic, The Codebrea...
Article
We review the history of the thermodynamics of information processing, beginning with the paradox of Maxwell's demon; continuing through the efforts of Szilard, Brillouin, and others to demonstrate a thermodynamic cost of information acquisition; the discovery by Landauer of the thermodynamic cost of information destruction; the development of the...
Article
Full-text available
In an effort to simplify the classification of pure entangled states of multi (m) -partite quantum systems, we study exactly and asymptotically (in n) reversible transformations among n'th tensor powers of such states (ie n copies of the state shared among the same m parties) under local quantum operations and classical communication (LOCC). With r...
Article
Rolf Landauer, an IBM Research scientist known for his pioneering work in electrical conductivity theory and the physics of information, died recently at age 72. In this Retrospective, Charles Bennett (page 1940) reflects on his life and his scientific achievements.
Article
Full-text available
Prior entanglement between sender and receiver, which exactly doubles the classical capacity of a noiseless quantum channel, can increase the classical capacity of some noisy quantum channels by an arbitrarily large constant factor depending on the channel, relative to the best known classical capacity achievable without entanglement. The enhanceme...
Article
Classical approaches to encoding information generally rely on using encryption protocols that are difficult for computers to crack, because the required mathematical operations are prohibitively slow on classical computers. However, the same encryption protocols will not work when quantum computers are developed, because these mathematical operati...
Article
By the year 2020, the basic memory components of a computer will be the size of individual atoms. At such scales, the current theory of computation will become invalid. A new field called "quantum computing" is emerging that is reinventing the foundations of computer science and information theory in a way that is consistent with quantum physics -...
Article
: We inquire under what conditions some of the information in a quantum signal source, namely a set of pure states / a emitted with probabilities p a , can be extracted in classical form by a measurement leaving the quantum system with less entropy than it had before, but retaining the ability to regenerate the source state exactly from the classic...
Article
This dissertation investigates a theory of the manipulation of quantum states and their protection against noise. This theory shows similarities to classical information theory, and crucial differences arising from fundamental differences between quantum and classical states. The classical theory plays an important role in computer science and comm...
Article
Full-text available
An unextendible product basis (UPB) for a multipartite quantum system is an incomplete orthogonal product basis whose complementary subspace contains no product state. We give examples of UPBs, and show that the uniform mixed state over the subspace complementary to any UPB is a bound entangled state. We exhibit a tripartite 2x2x2 UPB whose complem...
Article
An unknown quantum state jOEi can be disassembled into, then later reconstructed from, purely classical information and purely nonclassical EPR correlations. To do so the sender, "Alice," and the receiver, "Bob," must prearrange the sharing of an EPRcorrelated pair of particles. Alice makes a joint measurement on her EPR particle and the unknown qu...
Article
Full-text available
While Kolmogorov (1965) complexity is the accepted absolute measure of information content in an individual finite object, a similarly absolute notion is needed for the information distance between two individual objects, for example, two pictures. We give several natural definitions of a universal information metric, based on length of shortest pr...
Article
Full-text available
We exhibit an orthogonal set of product states of two three-state particles that nevertheless cannot be reliably distinguished by a pair of separated observers ignorant of which of the states has been presented to them, even if the observers are allowed any sequence of local operations and classical communication between the separate observers. It...
Article
Landauer's contributions to the physics of information transmission and processing are highlighted by figures and cartoons drawn by himself and others.
Article
The quantum analog of the classical erasure channel provides a simple example of a channel whose asymptotic capacity for faithful transmission of intact quantum states, with and without the assistance of a two-way classical side channel, can be computed exactly. We derive the quantum and classical capacities for the quantum erasure channel and rela...
Chapter
Quantum information theory has recently been enlarged to include the use of quantum channels for the transmission not only of classical information but also of intact quantum states. We survey known upper and lower bounds on the capacity of quantum channels, alone or assisted by one- or two-way classical communication, to transmit intact quantum st...
Article
Full-text available
We consider the problem of trying to send a single classical bit through a noisy quantum channel when two transmissions through the channel are available as a resource. Classically, two transmissions add nothing to the receiver's capability of inferring the bit. In the quantum world, however, one has the possible further advantage of entangling the...
Article
An $n$-bit string is encoded as a sequence of non-orthogonal quantum states. The parity bit of that $n$-bit string is described by one of two density matrices, $\rho_0^{(n)}$ and $\rho_1^{(n)}$, both in a Hilbert space of dimension $2^n$. In order to derive the parity bit the receiver must distinguish between the two density matrices, e.g., in term...
Article
Entanglement purification protocols (EPP) and quantum error-correcting codes (QECC) provide two ways of protecting quantum states from interaction with the environment. In an EPP, perfectly entangled pure states are extracted, with some yield D, from a mixed state M shared by two parties; with a QECC, an arbi- trary quantum state $|\xi\rangle$ can...
Article
Bel- Yorktown Heights, New York, NY 10598, USA; bennetc/divince@watson.ibm.com. l's inequalities, quantum cellular automata, and the "many-worlds" interpretation, have moved on to include some concrete discussions of experimental realizations of quantum logic gates --- to the extent that the paper[1] of the University of Innsbruck group, presented...
Article
Full-text available
If two separated observers are supplied with entanglement, in the form of $n$ pairs of particles in identical partly-entangled pure states, one member of each pair being given to each observer; they can, by local actions of each observer, concentrate this entanglement into a smaller number of maximally-entangled pairs of particles, for example Eins...
Article
Full-text available
This paper, provides a general treatment of privacy amplification by public discussion, a concept introduced by Bennett, Brassard, and Robert for a special scenario. Privacy amplification is a process that allows two parties to distil a secret key from a common random variable about which an eavesdropper has partial information. The two parties gen...
Article
Thpheoretical computer scientists, like their counterparts in physics, suffer and benefit from a high level of intellectual machismo. They believe they have some of the biggest brains around, which they need to think about some of the hardest problems. Like mathematicians, they prove theorems and doubt the seriousness of those who don't. Latel...
Article
A dynamical system is said to be computationally universal if it can be programmed through its initial condition to perform and digital computation. Such systems include traditional abstract computers such as Turing machines and cellular automata, as well as more physical models such as hard sphere gases and even a single particle in an appropriate...
Article
Full-text available
We show that a set of gates that consists of all one-bit quantum gates (U(2)) and the two-bit exclusive-or gate (that maps Boolean values $(x,y)$ to $(x,x \oplus y)$) is universal in the sense that all unitary operations on arbitrarily many bits $n$ (U($2^n$)) can be expressed as compositions of these gates. We investigate the number of the above g...
Article
A Comment on the Letter by P. M. Binder and V. Privman, Phys. Rev. Lett. 68, 3830 (1992).
Article
Nontrivial "complex" or "organized" states of a physical system may be characterized as those implausible save as the results of a long causal history or evolution. This notion, formalized by the tools of the theory of universal digital computers, is compared to other notions of complexity, and an attempt is made to sketch open problems in the comp...
Article
The analogy between temporally periodic phases of noisy extended driven systems and smooth interfaces in growth models is used to derive results for both problems, viz., stable, temporally quasiperiodic phases with long-range spatial order can in fact occur for noisy, short-range, isotropic rules in dimensions d>2. For d=2, temporally quasiperiodic...
Article
Full-text available
Intuitively, the minimal information distance between x and y is the length of the shortest program for a universal computer to transform x into y and y into x. This measure will be shown to be, up to a logarithmic additive term, equal to the maximum of the conditional Kolmogorov complexities E1(x,y) = max{k(y|x),K(x|y)}. It turns out that E1 is mi...
Article
Full-text available
An unknown quantum state ‖φ〉 can be disassembled into, then later reconstructed from, purely classical information and purely nonclassical Einstein-Podolsky-Rosen (EPR) correlations. To do so the sender, ‘‘Alice,’’ and the receiver, ‘‘Bob,’’ must prearrange the sharing of an EPR-correlated pair of particles. Alice makes a joint measurement on her E...
Article
As is well known, operations on one particle of an Einstein-Podolsky-Rosen (EPR) pair cannot influence the marginal statistics of measurements on the other particle. We characterize the set of states accessible from an initial EPR state by one-particle operations and show that in a sense they allow two bits to be encoded reliably in one spin-1/2 pa...

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