Conjugate Degradability and the Quantum Capacity of Cloning Channels (2009)
Bradler, Kamil, Dutil, Nicolas, Hayden, Patrick, Muhammad, Abubakr
A quantum channel is conjugate degradable if the channel's environment can be simulated up to complex conjugation using the channel's output. For all such channels, the quantum capacity can be...
The mother of all protocols: restructuring quantum information's family tree (2009)
Abeyesinghe, Anura, Devetak, Igor, Hayden, Patrick, Winter, Andreas
We give a simple, direct proof of the ‘mother’ protocol of quantum information theory. In this new formulation, it is easy to see that the mother, or rather her generalization to the fully...
Multiparty distributed compression of quantum information (2008)
Abstract—We study a protocol in which many parties use quantum communication to transfer a shared state to a receiver without communicating with each other. This protocol is a multiparty version of...
Possibility, impossibility, and cheat sensitivity of quantum-bit string commitment (2008)
Buhrman, Harry, Christandl, Matthias, Hayden, Patrick, Lo, Hoi-Kwong, Wehner, Stephanie
Counterexamples to the maximal p-norm multiplicativity conjecture for all p > 1 (2008)
Hayden, Patrick, Winter, Andreas
For all p > 1, we demonstrate the existence of quantum channels with non-multiplicative maximal output p-norms. Equivalently, for all p >1, the minimum output Renyi entropy of order p of a quantum...
Private information via the Unruh effect (2008)
Bradler, Kamil, Hayden, Patrick, Panangaden, Prakash
In a relativistic theory of quantum information, the possible presence of horizons is a complicating feature that places restrictions on the transmission and retrieval of information. In this...
Yard, Jon, Hayden, Patrick, Devetak, Igor
In this paper, we consider quantum channels with two senders and one receiver. For an arbitrary such channel, we give multiletter characterizations of two different two-dimensional capacity regions....
Random quantum codes from Gaussian ensembles and an uncertainty relation (2007)
Hayden, Patrick, Shor, Peter W., Winter, Andreas
Using random Gaussian vectors and an information-uncertainty relation, we give a proof that the coherent information is an achievable rate for entanglement transmission through a noisy quantum...
Black holes as mirrors: quantum information in random subsystems (2007)
Hayden, Patrick, Preskill, John
We study information retrieval from evaporating black holes, assuming that the internal dynamics of a black hole is unitary and rapidly mixing, and assuming that the retriever has unlimited control...
Black holes as mirrors: quantum information in random subsystems (2007)
Hayden, Patrick, Preskill, John
We study information retrieval from evaporating black holes, assuming that the internal dynamics of a black hole is unitary and rapidly mixing, and assuming that the retriever has unlimited control...
The maximal p-norm multiplicativity conjecture is false (2007)
For all 1 < p < 2, we demonstrate the existence of quantum channels with non-multiplicative maximal p-norms. Equivalently, the minimum output Renyi entropy of order p of a quantum channel is not...
Distributed Compression and Multiparty Squashed Entanglement (2007)
Avis, David, Hayden, Patrick, Savov, Ivan
We study a protocol in which many parties use quantum communication to transfer a shared state to a receiver without communicating with each other. This protocol is a multiparty version of the fully...
A decoupling approach to the quantum capacity (2007)
Hayden, Patrick, Horodecki, Michal, Yard, Jon, Winter, Andreas
We give a proof that the coherent information is an achievable rate for the transmission of quantum information through a noisy quantum channel. Our method is to select coding subspaces according to...
A father protocol for quantum broadcast channels (2006)
Dupuis, Frédéric, Hayden, Patrick
A new protocol for quantum broadcast channels based on the fully quantum Slepian-Wolf protocol is presented. The protocol yields an achievable rate region for entanglement-assisted transmission of...
On the Distributed Compression of Quantum Information (2006)
Ahn, Charlene, Doherty, Andrew C., Hayden, Patrick, Winter, Andreas J.
The problem of distributed compression for correlated quantum sources is considered. The classical version of this problem was solved by Slepian and Wolf, who showed that distributed compression...
Security of quantum bit string commitment depends on the information measure (2006)
Buhrman, Harry, Christandl, Matthias, Hayden, Patrick, Lo, Hoi-Kwong, Wehner, Stephanie
Unconditionally secure non-relativistic bit commitment is known to be impossible in both the classical and the quantum world. However, when committing to a string of n bits at once, how far can we...
Optimal Superdense Coding of Entangled States (2006)
Abeyesinghe, Anura, Hayden, Patrick, Smith, Graeme, Winter, Andreas J.
In this paper, we present a one-shot method for preparing pure entangled states between a sender and a receiver at a minimal cost of entanglement and quantum communication. In the case of preparing...
The mother of all protocols: Restructuring quantum information's family tree (2006)
Abeyesinghe, Anura, Devetak, Igor, Hayden, Patrick, Winter, Andreas
We give a simple, direct proof of the "mother" protocol of quantum information theory. In this new formulation, it is easy to see that the mother, or rather her generalization to the fully quantum...
Accurate quantum state estimation via "Keeping the experimentalist honest" (2006)
Blume-Kohout, Robin, Hayden, Patrick
In this article, we derive a unique procedure for quantum state estimation from a simple, self-evident principle: an experimentalist's estimate of the quantum state generated by an apparatus should...
Quantum broadcast channels (2006)
Yard, Jon, Hayden, Patrick, Devetak, Igor
We analyze quantum broadcast channels, which are quantum channels with a single sender and many receivers. Focusing on channels with two receivers for simplicity, we generalize a number of results...
Capacity Theorems for Quantum Multiple Access Channels (2005)
Yard, Jon, Devetak, Igor, Hayden, Patrick
We consider quantum channels with two senders and one receiver. For an arbitrary such channel, we give multi-letter characterizations of two different two-dimensional capacity regions. The first...
Random subspaces for encryption based on a private shared Cartesian frame (2005)
Bartlett, Stephen D., Hayden, Patrick, Spekkens, Robert W.
A private shared Cartesian frame is a novel form of private shared correlation that allows for both private classical and quantum communication. Cryptography using a private shared Cartesian frame...
Possibility, Impossibility and Cheat-Sensitivity of Quantum Bit String Commitment (2005)
Buhrman, Harry, Christandl, Matthias, Hayden, Patrick, Lo, Hoi-Kwong, Wehner, Stephanie
Unconditionally secure non-relativistic bit commitment is known to be impossible in both the classical and the quantum worlds. But when committing to a string of n bits at once, how far can we...
Yard, Jon, Devetak, Igor, Hayden, Patrick
We consider quantum channels with two senders and one receiver. For an arbitrary such channel, we give multi-letter characterizations of two different two-dimensional capacity regions. The first...
Remote preparation of quantum states (2005)
Bennett, Charles H., Hayden, Patrick, Leung, Debbie W., Shor, Peter W., Winter, Andreas
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...
Quantum state transformations and the Schubert calculus (2004)
Daftuar, Sumit, Hayden, Patrick
Recent developments in mathematics have provided powerful tools for comparing the eigenvalues of matrices related to each other via a moment map. In this paper we survey some of the more concrete...
Entanglement in Random Subspaces (2004)
The selection of random subspaces plays a role in quantum information theory analogous to the role of random strings in classical information theory. Recent applications have included protocols...
Correcting quantum channels by measuring the environment (2004)
Hayden, Patrick, King, Christopher
The corrected capacity of a quantum channel is defined as the best one-shot capacity that can be obtained by measuring the environment and using the result to correct the output of the channel. It is...
Multiparty data hiding of quantum information (2004)
Hayden, Patrick, Leung, Debbie, Smith, Graeme
We present protocols for multiparty data hiding of quantum information that implement all possible threshold access structures. Closely related to secret sharing, data hiding has a more demanding...
Optimal superdense coding of entangled states (2004)
Abeyesinghe, Anura, Hayden, Patrick, Smith, Graeme, Winter, Andreas
We present a one-shot method for preparing pure entangled states between a sender and a receiver at a minimal cost of entanglement and quantum communication. In the case of preparing unentangled...
Aspects of generic entanglement (2004)
Hayden, Patrick, Leung, Debbie W., Winter, Andreas
We study entanglement and other correlation properties of random states in high-dimensional bipartite systems. These correlations are quantified by parameters that are subject to the "concentration...
Superdense Coding of Quantum States (2004)
Harrow, Aram, Hayden, Patrick, Leung, Debbie
We describe a method for nonobliviously communicating a 2l-qubit quantum state by physically transmitting l + o(l) qubits, and by consuming l ebits of entanglement plus some shared random bits. In...
On the distributed compression of quantum information (2004)
Ahn, Charlene, Doherty, Andrew, Hayden, Patrick, Winter, Andreas
We consider the problem of distributed compression for correlated quantum sources. The classical version of this problem was solved by Slepian and Wolf, who showed that distributed compression could...
Abeyesinghe, Anura, Hayden, Patrick
We consider the problem of communicating quantum states by simultaneously making use of a noiseless classical channel, a noiseless quantum channel, and shared entanglement. We specifically study the...
Abeyesinghe, Anura, Hayden, Patrick
We consider the problem of communicating quantum states by simultaneously making use of a noiseless classical channel, a noiseless quantum channel and shared entanglement. We specifically study the...
Superdense coding of quantum states (2003)
Harrow, Aram, Hayden, Patrick, Leung, Debbie
We describe a method to non-obliviously communicate a 2l-qubit quantum state by physically transmitting l+o(l) qubits of communication, and by consuming l ebits of entanglement and some shared random...
Remote preparation of quantum states (2003)
Bennett, Charles H., Hayden, Patrick, Leung, Debbie W., Shor, Peter W., Winter, Andreas
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...
Randomizing quantum states: Constructions and applications (2003)
Hayden, Patrick, Leung, Debbie, Shor, Peter W., Winter, Andreas
The construction of a perfectly secure private quantum channel in dimension d is known to require 2 log d shared random key bits between the sender and receiver. We show that if only near-perfect...
Universal entanglement transformations without communication (2003)
We show that in the presence of finite catalysts, any pure bipartite entangled state can be converted into any other, to unlimited accuracy, without the use of any communication, quantum or...
Structure of states which satisfy strong subadditivity of quantum entropy with equality (2003)
Hayden, Patrick, Jozsa, Richard, Petz, Denes, Winter, Andreas
We give an explicit characterisation of the quantum states which saturate the strong subadditivity inequality for the von Neumann entropy. By combining a result of Petz characterising the equality...
Communication cost of entanglement transformations (2003)
Hayden, Patrick, Winter, Andreas
We study the amount of communication needed for two parties to transform some given joint pure state into another one, either exactly or with some fidelity. Specifically, we present a method to lower...
Trading quantum for classical resources in quantum data compression (2002)
Hayden, Patrick, Jozsa, Richard, Winter, Andreas
We study the visible compression of a source [script E] = {|phii>,pi} of pure quantum signal states or, more formally, the minimal resources per signal required to represent arbitrarily long strings...
DiVincenzo, David P., Hayden, Patrick, Terhal, Barbara M.
Recent work has shown how to use the laws of quantum mechanics to keep classical and quantum bits secret in a number of different circumstances. Among the examples are private quantum channels,...
On the communication cost of entanglement transformations (2002)
Hayden, Patrick, Winter, Andreas
We study the amount of communication needed for two parties to transform some given joint pure state into another one, either exactly or with some fidelity. Specifically, we present a method to lower...
Renyi-entropic bounds on quantum communication (2002)
In this article we establish new bounds on the quantum communication complexity of distributed problems. Specifically, we consider the amount of communication that is required to transform a...
Trading quantum for classical resources in quantum data compression (2002)
Hayden, Patrick, Jozsa, Richard, Winter, Andreas
We study the visible compression of a source E of pure quantum signal states, or, more formally, the minimal resources per signal required to represent arbitrarily long strings of signals with...
Embezzling Entangled Quantum States (2002)
We show that in the presence of arbitrary catalysts, any pure bipartite entangled state can be converted into any other to unlimited accuracy without the use of any communication, quantum or...
On the LOCC Classification of Bipartite Density Matrices (2000)
Hayden, Patrick, Terhal, Barbara M., Uhlmann, Armin
We provide a unifying framework for exact, probabilistic, and approximate conversions by local operations and classical communication (LOCC) between bipartite states. This framework allows us to...
On the reversible extraction of classical information from a quantum source (2000)
Barnum, Howard, Hayden, Patrick, Jozsa, Richard, Winter, Andreas
Consider a source E of pure quantum states with von Neumann entropy S. By the quantum source coding theorem, arbitrarily long strings of signals may be encoded asymptotically into S qubits/signal...
Basic concepts in quantum computation (2000)
Ekert, Artur, Hayden, Patrick, Inamori, Hitoshi
Section headings: 1 Qubits, gates and networks 2 Quantum arithmetic and function evaluations 3 Algorithms and their complexity 4 From interferometers to computers 5 The first quantum algorithms 6...
Basic Concepts in Quantum Computation (2000)
Artur Ekert, Patrick Hayden, Hitoshi Inamori
.95> j1i j1i j0i. In more compact notation: jai stands for the tensor product ja n 1 i ja n 2 i : : : ja 1 i ja 0 i, where a i 2 f0; 1g, and it represents a quantum register prepared with the...
Information Flow in Entangled Quantum Systems (1999)
Deutsch, David, Hayden, Patrick
All information in quantum systems is, notwithstanding Bell's theorem, localised. Measuring or otherwise interacting with a quantum system S has no effect on distant systems from which S is...