214 citations · 830 across the 10 of their papers we have counts for
10 papers
Can a spin-half particle ever give more than two spots in a Stern-Gerlach experiment? -- the subtle physics of effective Hamiltonians
Noah Linden, Sandu Popescu, Anthony J. Short
We show that a spin-1/2 particle can behave as if it were spin-, and generate spots in a Stern Gerlach measurement (albeit with a smaller gyromagnetic ratio). This arises…
The Hadamard gate cannot be replaced by a resource state in universal quantum computation
Benjamin D. M. Jones, Noah Linden, Paul Skrzypczyk
We consider models of quantum computation that involve operations performed on some fixed resourceful quantum state. Examples that fit this paradigm include magic state injection a…
Virtual qubits, virtual temperatures, and the foundations of thermodynamics
Nicolas Brunner, Noah Linden, Sandu Popescu +1
We argue that thermal machines can be understood from the perspective of `virtual qubits' at `virtual temperatures': The relevant way to view the two heat baths which drive a therm…
Optimal simulation of two-qubit Hamiltonians using general local operations
C. H. Bennett, J. I. Cirac, M. S. Leifer +4
We consider the simulation of the dynamics of one nonlocal Hamiltonian by another, allowing arbitrary local resources but no entanglement nor classical communication. We characteri…
Are all noisy quantum states obtained from pure ones?
L. Henderson, N. Linden, S. Popescu
We ask what type of mixed quantum states can arise when a number of separated parties start by sharing a pure quantum state and then this pure state becomes contaminated by noise.…
Entanglement capabilities of non-local Hamiltonians
W. Dür, G. Vidal, J. I. Cirac +2
We quantify the capability of creating entanglement for a general physical interaction acting on two qubits. We give a procedure for optimizing the generation of entanglement. We a…
Good dynamics versus bad kinematics. Is entanglement needed for quantum computation?
Noah Linden, Sandu Popescu
We consider quantum computing with pseudo-pure states. This framework arises in certain implementations of quantum computing using NMR. We analyze quantum computational protocols w…
Pulse Sequences for NMR Quantum Computers: How to Manipulate Nuclear Spins While Freezing the Motion of Coupled Neighbours
N Linden, H Barjat, RJ Carbajo +1
We show how to divide a coupled multi-spin system into a small subset of ``active'' spins that evolve under chemical shift or scalar coupling operators, and a larger subset of ``sp…
Bound Entanglement and Teleportation
N Linden, S Popescu
Recently M. Horodecki, P. Horodecki and R. Horodecki have introduced a set of density matrices of two spin-1 particles from which it is not possible to distill any maximally entang…
Purifying noisy entanglement requires collective measurements
N. Linden, S. Massar, S. Popescu
Known entanglement purification protocols for mixed states use collective measurements on several copies of the state in order to increase the entanglement of some of them. We addr…