Work and Quantum Phase Transitions: Is there Quantum Latency?

We study the physics of quantum phase transitions from the perspective of non-equilibrium thermodynamics. For first order quantum phase transitions, we find that the average work done per quench in crossing the critical point is discontinuous. This leads us to introduce the quantum latent work in analogy with the classical latent heat of first order classical phase transitions. For second order quantum phase transitions the irreversible work is closely related to the fidelity susceptibility for weak sudden quenches of the system Hamiltonian. We demonstrate our ideas with numerical simulations of first, second, and infinite order phase transitions in various spin chain models.Comment: accepted in PR

Non-Markovianity, Loschmidt echo and criticality: a unified picture

A simple relationship between recently proposed measures of non-Markovianity and the Loschmidt echo is established, holding for a two-level system (qubit) undergoing pure dephasing due to a coupling with a many-body environment. We show that the Loschmidt echo is intimately related to the information flowing out from and occasionally back into the system. This, in turn, determines the non-Markovianity of the reduced dynamics. In particular, we consider a central qubit coupled to a quantum Ising ring in the transverse field. In this context, the information flux between system and environment is strongly affected by the environmental criticality; the qubit dynamics is shown to be Markovian exactly and only at the critical point. Therefore non-Markovianity is an indicator of criticality in the model considered here

Teleportation of a quantum state of a spatial mode with a single massive particle

Mode entanglement exists naturally between regions of space in ultra-cold atomic gases. It has, however, been debated whether this type of entanglement is useful for quantum protocols. This is due to a particle number superselection rule that restricts the operations that can be performed on the modes. In this paper, we show how to exploit the mode entanglement of just a single particle for the teleportation of an unknown quantum state of a spatial mode. We detail how to overcome the superselection rule to create any initial quantum state and how to perform Bell state analysis on two of the modes. We show that two of the four Bell states can always be reliably distinguished, while the other two have to be grouped together due to an unsatisfied phase matching condition. The teleportation of an unknown state of a quantum mode thus only succeeds half of the time.Comment: 12 pages, 1 figure, this paper was presented at TQC 2010 and extends the work of Phys. Rev. Lett. 103, 200502 (2009

Aldose Reductase Gene Polymorphisms and Diabetic Retinopathy Susceptibility

OBJECTIVE: Aldose reductase (ALR) is involved in diabetic microvascular damage via the polyol pathway. A recent meta-analysis found genetic variation in the ALR gene (AKR1B1) to be significantly associated with diabetic retinopathy (DR). We investigated the genetic association of AKR1B1 with DR. RESEARCH DESIGN AND METHODS: The study enrolled 909 individuals with diabetes. Participants were genotyped for an AKR1B1 (CA)n microsatellite and 14 tag single nucleotide polymorphisms, and ophthalmological assessment was performed. RESULTS: A total of 514 individuals were found to have DR. rs9640883 was significantly associated with DR (P = 0.0005). However, AKR1B1 variation was not independently associated with DR development after adjusting for relevant clinical parameters. rs9640883 was associated with duration of diabetes (P = 0.002). CONCLUSION: Many previous reports have failed to account for known risk factors for DR. The commonly reported association of AKR1B1 with DR may be due to an association of the gene with younger age at onset of diabetes.Sotoodeh Abhary, Kathryn P. Burdon, Kate J. Laurie, Stacey Thorpe, John Landers, Lucy Goold, Stewart Lake, Nikolai Petrovsky, and Jamie E. Crai

The Emergence and Evolution of the Multidimensional Organization

The article discusses multidimensional organizations and the evolution of complex organizations. The six characteristics of multidimensional organizations, disadvantages of the successful organizational structure that is categorized as a multidivisional, multi-unit or M-form, research by the Foundation for Management Studies which suggests that synergies across business divisions can be exploited by the M-form, a team approach to creating economic value, examples of multidimensional firms such as PricewaterhouseCoopers, and a comparison of various organization types including the matrix form are mentioned

On defining the Hamiltonian beyond quantum theory

Energy is a crucial concept within classical and quantum physics. An essential tool to quantify energy is the Hamiltonian. Here, we consider how to define a Hamiltonian in general probabilistic theories, a framework in which quantum theory is a special case. We list desiderata which the definition should meet. For 3-dimensional systems, we provide a fully-defined recipe which satisfies these desiderata. We discuss the higher dimensional case where some freedom of choice is left remaining. We apply the definition to example toy theories, and discuss how the quantum notion of time evolution as a phase between energy eigenstates generalises to other theories.Comment: Authors' accepted manuscript for inclusion in the Foundations of Physics topical collection on Foundational Aspects of Quantum Informatio

In-Flight Testing of MEMS Pressure Sensors for Flight Loads Determination

The determination and monitoring of structural loads during flight is an important partof every certification program. It must be proved to the certification authorities that the loads occurring during specific flight maneuvers do not exceed the permissible component loads. Usually conventional strain gauges are used to determine structural loads, however an elaborate calibration process is necessary to determine these loads from the measuredstrains. Recent advances in sensor technology allow determining aerodynamic loads directly from pressure distributions measured by MEMS based sensors. When compared to strain gauges this measurement method has several advantages over conventional strain gauges interms of installation and calibration costs. Flight tests were carried out with the DLR researchglider aircraft Discus-2c in order to compare and investigate the loads determined with the two measuring methods. For this purpose a wing glove equipped with 64 MEMS pressure sensors on the airfoil surface was constructed. Different maneuvers with varying loads were performed during the test flights. A first evaluation of steady flight maneuvers shows that theloads determined from the measured pressure distribution are in very good accordance with the ones determined from the strain gauge measurements. This paper gives an overview of the flight test setup and the data analysis process, results from evaluations of trimmed wings-level flight and steady turn maneuvers are presented and discussed

ReveaLLAGN 0: First Look at JWST MIRI data of Sombrero and NGC 1052

We present the first results from the Revealing Low-Luminosity Active Galactic Nuclei (ReveaLLAGN) survey, a JWST survey of seven nearby LLAGN. We focus on two observations with the Mid-Infrared Instrument's (MIRI) Medium Resolution Spectrograph (MRS) of the nuclei of NGC 1052 and Sombrero (NGC 4594 / M104). We also compare these data to public JWST data of a higher-luminosity AGN, NGC 7319. JWST clearly resolves the AGN component even in Sombrero, the faintest target in our survey; the AGN components have very red spectra. We find that the emission-line widths in both NGC 1052 and Sombrero increase with increasing ionization potential, with FWHM > 1000 km/s for lines with ionization potential > 50 eV. These lines are also significantly blue-shifted in both LLAGN. The high ionization potential lines in NGC 7319 show neither broad widths or significant blue shifts. Many of the lower ionization potential emission lines in Sombrero show significant blue wings extending > 1000 km/s. These features and the emission-line maps in both galaxies are consistent with outflows along the jet direction. Sombrero has the lowest luminosity high-ionization potential lines ([Ne V] and [O IV]) ever measured in the mid-IR, but the relative strengths of these lines are consistent with higher luminosity AGN. On the other hand, the [Ne V] emission is much weaker relative to the [Ne III}] and [Ne II] lines of higher-luminosity AGN. These initial results show the great promise that JWST holds for identifying and studying the physical nature of LLAGN.Comment: Submitted to Ap

Eigenvectors under a generic perturbation: non-perturbative results from the random matrix approach

We consider eigenvectors of the Hamiltonian H0 perturbed by a generic perturbation V modelled by a random matrix from the Gaussian Unitary Ensemble (GUE). Using the super-symmetry approach we derive analytical results for the statistics of the eigenvectors, which are non-perturbative in V and valid for an arbitrary deterministic H0. Further we generalise them to the case of a random H0, focusing, in particular, on the Rosenzweig-Porter model. Our analytical predictions are confirmed by numerical simulations

DFT-inspired methods for quantum thermodynamics

In the framework of quantum thermodynamics, we propose a method to quantitatively describe thermodynamic quantities for out-of-equilibrium interacting many-body systems. The method is articulated in various approximation protocols which allow to achieve increasing levels of accuracy, it is relatively simple to implement even for medium and large number of interactive particles, and uses tools and concepts from density functional theory. We test the method on the driven Hubbard dimer at half filling, and compare exact and approximate results. We show that the proposed method reproduces the average quantum work to high accuracy: for a very large region of parameter space (which cuts across all dynamical regimes) estimates are within 10% of the exact results