Daniel Braun

Comment on "Regional Versus Global Entanglement in Resonating-Valence-Bond States" (2008)

English

Alet, Fabien, Braun, Daniel, Misguich, Grégoire

In a recent Letter [Phys. Rev. Lett. 99, 170502 (2007); quant-ph/0703227], Chandran and coworkers study the entanglement properties of valence bond (VB) states. Their main result is that VB states do...

Hardy's Test versus the CHSH Test of Quantum Non-Locality: Fundamental and Practical Aspects (2008)

Braun, Daniel, Choi, Mahn-Soo

We compare two different tests of quantum non-locality, both in theoretical terms and with respect to a possible implementation in a mesoscopic circuit: Hardy's test [Hardy, Phys. Rev. Lett....

Quantum Cloning without Interference (2008)

Roubert, Benoit, Braun, Daniel

We study the role of interference in the process of quantum cloning. We show that in order to achieve better than classical cloning of a qubit no interference is needed. In particular, a large class...

Efficiency of Producing Random Unitary Matrices with Quantum Circuits (2008)

Arnaud, Ludovic, Braun, Daniel

We study the scaling of the convergence of several statistical properties of a recently introduced random unitary circuit ensemble towards their limits given by the circular unitary ensemble (CUE)....

Classicality of spin states (2008)

Giraud, Olivier, Braun, Petr, Braun, Daniel

We extend the concept of classicality in quantum optics to spin states. We call a state ``classical'' if its density matrix can be decomposed as a weighted sum of angular momentum coherent states...

Classicality of spin states (2008)

Giraud, Olivier, Braun, Petr, Braun, Daniel

We extend the concept of classicality in quantum optics to spin states. We call a state ``classical'' if its density matrix can be decomposed as a weighted sum of angular momentum coherent states...

Classicality of spin states (2008)

Giraud, Olivier, Braun, Petr, Braun, Daniel

We extend the concept of classicality in quantum optics to spin states. We call a state ``classical'' if its density matrix can be decomposed as a weighted sum of angular momentum coherent states...

H]/ C, Aromatic C H, Konstantin Pervushin, Daniel Braun, César Fernández, Kurt Wüthrich

This paper describes a [ 15N, 1H]/ [ 13C, 1H]-TROSY experiment for the simultaneous acquisition of the heteronuclear chemical shift correlations of backbone amide 15N – 1H groups, side chain 15N...

Interference versus success probability in quantum algorithms with imperfections (2007)

Spontaneous emission from a two--level atom tunneling in a double--well potential (2007)

We study the influence of errors and decoherence on both the performance of Shor's factoring algorithm and Grover's search algorithm, and on the amount of interference in these algorithms using a...

Braun, Daniel, Martin, John

We study a two-level atom in a double--well potential coupled to a continuum of electromagnetic modes (black body radiation in three dimensions at zero absolute temperature). Internal and external...

Exact Activation Energy of Magnetic Single Domain Particles (2007)

Role of interference in quantum state transfer through spin chains (2007)

I present the exact analytical expression for the activation energy as a function of externally applied magnetic fields for a single--domain magnetic particle with uniaxial anisotropy...

Lyakhov, A. O., Braun, Daniel, Bruder, C.

We examine the role that interference plays in quantum state transfer through several types of finite spin chains, including chains with isotropic Heisenberg interaction between nearest neighbors,...

Coherent control of atomic tunneling (2007)

Martin, John, Braun, Daniel

We study the tunneling of a two-level atom in a double well potential while the atom is coupled to a single electromagnetic field mode of a cavity. The coupling between internal and external degrees...

Decoherence in a system of many two--level atoms (2007)

Invariant integration over the orthogonal group (2007)

I show that the decoherence in a system of $N$ degenerate two--level atoms interacting with a bosonic heat bath is for any number of atoms $N$ governed by a generalized Hamming distance (called...

Distribution of interference in random quantum algorithms (2007)

I adapt a recently introduced method for integrating over the unitary group (S. Aubert and C.S. Lam, J.Math.Phys. 44, 6112-6131 (2003)) to the orthogonal group. I derive explicit formulas for a...

Arnaud, Ludovic, Braun, Daniel

We study the amount of interference in random quantum algorithms using a recently derived quantitative measure of interference. To this end we introduce two random circuit ensembles composed of...

Entanglement from thermal black body radiation (2007)

Effect of crystalline disorder on magnetic switching in small magnetic cells (2007)

Two non--interacting quantum systems which couple to a common environment with many degrees of freedom initially in thermal equilibrium can become entangled due to the indirect interaction mediated...

Unversality of decoherence in the macroworld (2007)

I present a study of the influence of disorder in thin magnetic films on the switching behavior of small magnetic cells of well defined shape and size. The disorder considered arises from randomly...

Strunz, Walter T., Haake, Fritz, Braun, Daniel

We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$...

Creation of Entanglement by Interaction with a Common Heat Bath (2007)

Quantum Chaos and Quantum Algorithms (2007)

I show that entanglement between two qubits can be generated if the two qubits interact with a common heat bath in thermal equilibrium, but do not interact directly with each other. In most...

Universality of Decoherence (2007)

It was recently shown (quant-ph/9909074) that parasitic random interactions between the qubits in a quantum computer can induce quantum chaos and put into question the operability of a quantum...

Braun, Daniel, Haake, Fritz, Strunz, Walter T.

We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$...

Long-lived Quantum Coherence between Macroscopically Distinct States in Superradiance (2007)

Slow Decoherence of Superpositions of Macroscopically Distinct States (2007)

The dephasing influence of a dissipative environment reduces linear superpositions of macroscopically distinct quantum states (sometimes also called Schr\"odinger cat states) usually almost...

Driving Atoms Into Decoherence-Free States (2007)

Linear superpositions of macroscopically distinct quantum states (sometimes also called Schr\"odinger cat states) are usually almost immediately reduced to a statistical mixture if exposed to the...

Beige, Almut, Braun, Daniel, Knight, Peter L.

We describe the decoherence-free subspace of N atoms in a cavity, in which decoherence due to the leakage of photons through the cavity mirrors is suppressed. We show how the states of the subspace...

Semiclassical spin damping: Superradiance revisited (2007)

Braun, Petr A., Braun, Daniel, Haake, Fritz, Weber, Joachim

A well known description of superradiance from pointlike collections of many atoms involves the dissipative motion of a large spin. The pertinent ``superradiance master equation'' allows for a...

Distribution of interference in random quantum algorithms (2006)

Arnaud, Ludovic, Braun, Daniel

We study the amount of interference in random quantum algorithms using a recently derived quantitative measure of interference. To this end we introduce two random circuit ensembles composed of...

Invariant integration over the orthogonal group (2006)

Indirect decoherence in optical lattices and cold gases (2006)

I adapt a recently introduced method for integrating over the unitary group (S. Aubert and C.S. Lam, J.Math.Phys. 44, 6112-6131 (2003)) to the orthogonal group. I derive explicit formulas for a...

Decoherence in a system of many two--level atoms (2005)

The interaction of two--level atoms with a common heat bath leads to an effective interaction between the atoms, such that with time the internal degrees of the atoms become correlated or even...

I show that the decoherence in a system of $N$ degenerate two--level atoms interacting with a bosonic heat bath is for any number of atoms $N$ governed by a generalized Hamming distance (called...

We introduce an interference measure which allows to quantify the amount of interference present in any physical process that maps an initial density matrix to a final density matrix. In particular,...

Entanglement from thermal black body radiation (2005)

We introduce an interference measure which allows to quantify the amount of interference present in any physical process that maps an initial density matrix to a final density matrix. In particular,...

Two non--interacting quantum systems which couple to a common environment with many degrees of freedom initially in thermal equilibrium can become entangled due to the indirect interaction mediated...

We introduce an interference measure which allows to quantify the amount of interference present in any physical process that maps an initial density matrix to a final density matrix. In particular,...

The Development of Permanent Medical Standards for Landing Craft Air Cushion (LCAC) Crew Personnel. (2005)

We introduce an interference measure which allows to quantify the amount of interference present in any physical process that maps an initial density matrix to a final density matrix. In particular,...

Hunt, Phillip, Linnville, Steven, Stuster, Jack, Schneider, Kevin, Braun, Daniel

Initially, the Naval Sea Systems Command (NAVSEA) provided Landing Craft Air Cushion (LCAC) crews with medical requirements for both selection and operational use in the 'Safe Engineering and...

Welchen Einfluss haben Musik und Rhythmus sowie eine initiale Videopräsentation auf die Durchführung von Thoraxkompressionen im Rahmen der Reanimation? / (2004)

Die Milchkompositionen bei Säugetieren und Mensch / (2004)

Diss. med. Basel (kein Austausch).

Effect of crystalline disorder on magnetic switching in small magnetic cells (2003)

Zugl.: Witten, Herdecke, Universiẗat, Privatuniv., Diss., 1997.

Creation of Entanglement by Interaction with a Common Heat Bath (2002)

I present a study of the influence of disorder in thin magnetic films on the switching behavior of small magnetic cells of well defined shape and size. The disorder considered arises from randomly...

Unversality of decoherence in the macroworld (2002)

I show that entanglement between two qubits can be generated if the two qubits interact with a common heat bath in thermal equilibrium, but do not interact directly with each other. In most...

Strunz, Walter T., Haake, Fritz, Braun, Daniel

We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$...

Quantum Chaos and Quantum Algorithms (2001)

Boundary Conditions, the Critical Conductance Distribution, and One-Parameter Scaling (2001)

It was recently shown (quant-ph/9909074) that parasitic random interactions between the qubits in a quantum computer can induce quantum chaos and put into question the operability of a quantum...

Braun, Daniel, Hofstetter, Etienne, Montambaux, Gilles, MacKinnon, Angus

We study the influence of boundary conditions transverse to the transport direction for disordered mesoscopic conductors both at the Anderson metal-insulator transition and in the metallic regime. We...

Universality of Decoherence (2001)

Braun, Daniel, Haake, Fritz, Strunz, Walter T.

Universality of Decoherence (2000)

Braun, Daniel, Haake, Fritz, Strunz, Walter T.

We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$...

Sequence-specific NMR assignment of proteins by global fragment mapping with program Mapper (2000)

Peter Güntert, Michael Salzmann, Daniel Braun, Kurt Wüthrich

triple resonance experiments A new program, MAPPER, for semiautomatic sequence-specific NMR assignment in proteins is introduced. The program uses an input of short fragments of sequentially...

Driving Atoms Into Decoherence-Free States (1999)

Beige, Almut, Braun, Daniel, Knight, Peter L.

We describe the decoherence-free subspace of N atoms in a cavity, in which decoherence due to the leakage of photons through the cavity mirrors is suppressed. We show how the states of the subspace...

Dissipative Chaotic Quantum Maps: Expectation Values, Correlation Functions and the Invariant State (1999)

Critical statistics in a power-law random banded matrix ensemble (1999)

I investigate the propagator of the Wigner function for a dissipative chaotic quantum map. I show that a small amount of dissipation reduces the propagator of sufficiently smooth Wigner functions to...

Varga, Imre, Braun, Daniel

We investigate the statistical properties of the eigenvalues and eigenvectors in a random matrix ensemble with $H_{ij}\sim |i-j|^{-\mu}$. It is known that this model shows a...

Spectral properties of Dissipative Chaotic Quantum Maps (1999)

Long-lived Quantum Coherence between Macroscopically Distinct States in Superradiance (1999)

I examine spectral properties of a dissipative chaotic quantum map with the help of a recently discovered semiclassical trace formula. I show that in the presence of a small amount of dissipation the...

Slow Decoherence of Superpositions of Macroscopically Distinct States (1999)

The dephasing influence of a dissipative environment reduces linear superpositions of macroscopically distinct quantum states (sometimes also called Schr\"odinger cat states) usually almost...

WKB for a damped spin (1998)

Linear superpositions of macroscopically distinct quantum states (sometimes also called Schr\"odinger cat states) are usually almost immediately reduced to a statistical mixture if exposed to the...

Braun, Petr A., Braun, Daniel, Haake, Fritz

The master equation for a damped spin well known from the theory of superradiance, is written as a finite-difference equation and solved by a WKB-like method. The propagator thus obtained looks like...

Semiclassics for a Dissipative Quantum Map (1998)

Semiclassical spin damping: Superradiance revisited (1998)

We present a semiclassical analysis for a dissipative quantum map with an area-nonpreserving classical limit. We show that in the limit of Planck's constant to 0 the trace of an arbitrary natural...

Braun, Petr A., Braun, Daniel, Haake, Fritz, Weber, Joachim

A well known description of superradiance from pointlike collections of many atoms involves the dissipative motion of a large spin. The pertinent ``superradiance master equation'' allows for a...

Die Milchkompositionen der Säugetiere im Vergleich und die Milch des Menschen [microform] / (1997)

Log-normal Distribution of Level Curvatures in the Localized Regime: Analytical Verification (1996)

Mikrofiche-Ausg.: Egelsbach ; Frankfurt (Main) ; Washington : Hänsel-Hohenhausen, 1997. 4 Mikrofiches.

Titov, Michael, Braun, Daniel, Fyodorov, Yan V.

We study numerically and analytically the moments of the dimensionless level curvature for one-dimensional disordered rings of the circumference L pierced by a magnetic flux. The negative moments of...

Magnetization of Disordered Ballistic Quantum Billards (1994)

Braun, Daniel, Gefen, Yuval, Montambaux, Gilles

We study the magnetic response of mesoscopic quantum dots in the ballistic regime where the mean free path $l_e$ is larger that the size $L$ of the sample, yet smaller than $L (k_F L)^{d-1}$. In this...

Universal Spectral Correlations in Diffusive Quantum Systems (1994)

Braun, Daniel, Montambaux, Gilles

We have studied numerically several statistical properties of the spectra of disordered electronic systems under the influence of an Aharonov Bohm flux $\varphi$, which acts as a time--reversal...

Single level current and curvature distributions in mesoscopic systems (1994)

Single level current and curvature distributions in mesoscopic systems (1994)

Exact analytic results for single level current and curvature distribution functions are derived within the framework of a 2×2 random matrix model. Current and curvature are defined as the first and...

Single level current and curvature distributions in mesoscopic systems (1994)

Exact analytic results for single level current and curvature distribution functions are derived within the framework of a 2×2 random matrix model. Current and curvature are defined as the first and...

Magnetic Response of Disordered Ballistic Quantum Dots (1993)

Exact analytic results for single level current and curvature distribution functions are derived within the framework of a 2×2 random matrix model. Current and curvature are defined as the first and...

Gefen, Yuval, Braun, Daniel, Montambaux, Gilles

The weak field average magnetic susceptibility of square shaped mesoscopic conductors is studied within a semiclassical framework. Long semiclassical trajectories are strongly affected by static...

Single Level Current and Curvature Distributions in Mesoscopic Systems (1993)

Judicium sortis per indicem ... (1652)

Exact analytic results for single level current and curvature distribution functions are derived in a framework of a $2\times 2$ random matrix model. Current and curvature are defined as the first...