131 citations · 512 across the 18 of their papers we have counts for
11 papers · 1 filter
Directional emission of single photons from small atomic samples
Yevhen Miroshnychenko, Uffe V. Poulsen, Klaus Mølmer
We provide a formalism to describe deterministic emission of single photons with tailored spatial and temporal profiles from a regular array of multi-level atoms. We assume that a…
Correcting errors in a quantum gate with pushed ions via optimal control
U. V. Poulsen, S. Sklarz, D. Tannor +1
We analyze in detail the so-called "pushing gate" for trapped ions, introducing a time dependent harmonic approximation for the external motion. We show how to extract the average…
Correlations in local measurements on a quantum state, and complementarity as an explanation of nonclassicality
Shengjun Wu, Uffe V. Poulsen, Klaus Mølmer
We consider the classical correlations that two observers can extract by measurements on a bipartite quantum state, and we discuss how they are related to the quantum mutual inform…
Atomic quantum superposition state generation via optical probing
Anne E. B. Nielsen, Uffe V. Poulsen, Antonio Negretti +1
We analyze the performance of a protocol to prepare an atomic ensemble in a superposition of two macroscopically distinguishable states. The protocol relies on conditional measurem…
Quantum Superposition State Production by Continuous Observations and Feedback
Antonio Negretti, Uffe V. Poulsen, Klaus Molmer
We present a protocol for generation of superpositions of states with distinguishable field amplitudes in an optical cavity by quantum nondemolition photon number measurements and…
Infinite qubit rings with maximal nearest neighbor entanglement: the Bethe ansatz solution
U. V. Poulsen, T. Meyer, D. Bruss +1
We search for translationally invariant states of qubits on a ring that maximize the nearest neighbor entanglement. This problem was initially studied by O'Connor and Wootters [Phy…
Differential atom interferometry beyond the standard quantum limit
K. Eckert, P. Hyllus, D. Bruss +6
We analyze methods to go beyond the standard quantum limit for a class of atomic interferometers, where the quantity of interest is the difference of phase shifts obtained by two i…
Unitarity as preservation of entropy and entanglement in quantum systems
Florian Hulpke, Uffe V. Poulsen, Anna Sanpera +3
The logical structure of Quantum Mechanics (QM) and its relation to other fundamental principles of Nature has been for decades a subject of intensive research. In particular, the…
Finite size effects in entangled rings of qubits
T. Meyer, U. V. Poulsen, K. Eckert +2
We study translationally invariant rings of qubits with a finite number of sites N, and find the maximal nearest-neighbor entanglement for a fixed z component of the total spin. Fo…
Squeezed light from spin squeezed atoms
U. V. Poulsen, K. Molmer
We propose to produce pulses of strongly squeezed light by Raman scattering of a strong laser pulse on a spin squeezed atomic sample. We prove that the emission is restricted to a…
Positive P simulations of spin squeezing in a two-component Bose condensate
Uffe V. Poulsen, Klaus Molmer
The collisional interaction in a Bose condensate represents a non-linearity which in analogy with non-linear optics gives rise to unique quantum features. In this paper we apply a…