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19922026
Showing 2008 · quant-phShow all

14 papers · 2 filters

quant-ph2008★ 2 cited

Wigner function for twisted photons

I. Rigas, L. L. Sanchez-Soto, A. B. Klimov +2

A comprehensive theory of the Weyl-Wigner formalism for the canonical pair angle-angular momentum is presented, with special emphasis in the implications of rotational periodicity…

quant-ph2008★ 55 cited

Competing many-body interactions in systems of trapped ions

A. Bermudez, D. Porras, M. A. Martin-Delgado

We propose and theoretically analyse an experimental configuration in which lasers induce 3-spin interactions between trapped ions.By properly choosing the intensities and frequenc…

quant-ph2008★ 25 cited

Preparation of Decoherence Free Cluster States with Optical Superlattices

Liang Jiang, Ana Maria Rey, Oriol Romero-Isart +3

We present a protocol to prepare decoherence free cluster states using ultracold atoms loaded in a two dimensional superlattice. The superlattice geometry leads to an array of 2*2…

quant-ph2008★ 17 cited

Constrained optimization of sequentially generated entangled multiqubit states

Hamed Saberi, Andreas Weichselbaum, Lucas Lamata +3

We demonstrate how the matrix-product state formalism provides a flexible structure to solve the constrained optimization problem associated with the sequential generation of entan…

quant-ph2008★ 8 cited

Discrete coherent states for n qubits

C. Munoz, A. B. Klimov, L. L. Sanchez-Soto +1

Discrete coherent states for a system of qubits are introduced in terms of eigenstates of the finite Fourier transform. The properties of these states are pictured in phase spa…

quant-ph2008★ 40 cited

Nonclassicality of states and measurements by breaking classical bounds on statistics

Ángel Rivas, Alfredo Luis

We derive exceedingly simple practical procedures revealing the quantum nature of states and measurements by the violation of classical upper bounds on the statistics of arbitrary…

quant-ph2008★ 111 cited

Security of Binary Modulated Continuous Variable Quantum Key Distribution under Collective Attacks

Yi-Bo Zhao, Matthias Heid, Johannes Rigas +1

We give an achievable secret key rate of a binary modulated continuous variable quantum key distribution schemes in the collective attack scenario considering quantum channels that…

quant-ph2008★ 37 cited

Quantum instability and edge entanglement in a quasi-long-range order

Wonmin Son, Luigi Amico, Francesco Plastina +1

We investigate the build-up of quasi-long-range order in the XX chain with transverse magnetic field at finite size. As the field is varied, the ground state of the system displays…

quant-ph2008★ 9 cited

Practical schemes for the measurement of angular-momentum covariance matrices in quantum optics

Ángel Rivas, Alfredo Luis

We develop practical schemes for the measurement of the covariance matrix for intrinsic angular-momentum variables in quantum optics. We particularize this approach to two-beam pol…

quant-ph2008★ 22 cited

Full quantum reconstruction of vortex states

I. Rigas, L. L. Sanchez-Soto, A. B. Klimov +2

We propose a complete tomographic reconstruction of any vortex state carrying orbital angular momentum. The scheme determines the angular probability distribution of the state at d…

quant-ph2008★ 36 cited

Discrete phase-space structure of -qubit mutually unbiased bases

A. B. Klimov, J. L. Romero, G. Bjork +1

We work out the phase-space structure for a system of qubits. We replace the field of real numbers that label the axes of the continuous phase space by the finite field $\Gal{2…

quant-ph2008★ 54 cited

Sequentially generated states for the study of two dimensional systems

Mari-Carmen Bañuls, David Pérez-García, Michael M. Wolf +2

Matrix Product States can be defined as the family of quantum states that can be sequentially generated in a one-dimensional system. We introduce a new family of states which exten…

quant-ph2008★ 115 cited

Chirality Quantum Phase Transition in the Dirac oscillator

A. Bermudez, M. A. Martin-Delgado, A. Luis

We study a relativistic spin-1/2 fermion subjected to a Dirac oscillator coupling and a constant magnetic field. An interplay between opposed chirality interactions culminates in t…

quant-ph2008★ 18 cited

Intrinsic metrological resolution as a distance measure and nonclassical light

Ángel Rivas, Alfredo Luis

We elaborate on a Hilbert-Schmidt distance measure assessing the intrinsic metrological accuracy in the detection of signals imprinted on quantum probe states by signal-dependent t…