Symmetry-Assisted Preparation of Entangled Many-Body States on a Quantum Computer.

Starting from the quantum-phase-estimate (QPE) algorithm, a method is proposed to construct entangled states that describe correlated many-body systems on quantum computers. Using operators for which the discrete set of eigenvalues is known, the QPE approach is followed by measurements that serve as projectors on the entangled states. These states can then be used as inputs for further quantum or hybrid quantum-classical processing. When the operator is associated with a symmetry of the Hamiltonian, the approach can be seen as a quantum-computer formulation of symmetry breaking followed by symmetry restoration. The method, called discrete spectra assisted, is applied to superfluid systems. By using the blocking technique adapted to qubits, the full spectra of a pairing Hamiltonian is obtained.

Erratum: Microscopic Phase-Space Exploration Modeling of

This corrects the article DOI: 10.1103/PhysRevLett.118.152501.

Microscopic Phase-Space Exploration Modeling of

We show that the total kinetic energy (TKE) of nuclei after the spontaneous fission of ^{258}Fm can be well reproduced using simple assumptions on the quantum collective phase space explored by the nucleus after passing the fission barrier. Assuming energy conservation and phase-space exploration according to the stochastic mean-field approach, a set of initial densities is generated. Each density is then evolved in time using the nuclear time-dependent density-functional theory with pairing. This approach goes beyond the mean-field theory by allowing spontaneous symmetry breaking as well as a wider dynamical phase-space exploration leading to larger fluctuations in collective space. The total kinetic energy and mass distributions are calculated. New information on the fission process: fluctuations in scission time, strong correlation between TKE and collective deformation, as well as prescission particle emission, are obtained. We conclude that fluctuations of the TKE and mass are triggered by quantum fluctuations.

Probing neutron correlations through nuclear breakup.

The effect of initial correlations between nucleons on the nuclear breakup mechanism is studied. A quantum transport theory which extends the standard mean-field approach is developed to incorporate short range pairing correlation as well as direct nucleon-nucleon collisions. A time evolution of the nuclear breakup from a correlated system leading to the emission of two particles to the continuum is performed. We show that initial correlations have strong influence on relative angles between particles emitted in coincidence. The present qualitative study indicates that nuclear breakup might be a tool to infer the residual interaction between nucleons in the nuclear medium.

Stochastic simulation of dissipation and non-Markovian effects in open quantum systems.

The exact dynamics of a system coupled to an environment can be described by an integro-differential stochastic equation for the reduced density. The influence of the environment is incorporated through a mean field which is both stochastic and nonlocal in time and where the standard two-time correlation functions of the environment appear naturally. Since no approximation is made, the presented theory incorporates exactly dissipative and non-Markovian effects. Applications to the spin-boson model coupled to a heat bath with various coupling regimes and temperature show that the presented stochastic theory can be a valuable tool to simulate exactly the dynamics of open quantum systems. Links with the stochastic Schrödinger equation method and possible extensions to "imaginary time" propagation are discussed.

Risperidone does not affect steady-state pharmacokinetics of divalproex sodium in patients with bipolar disorder.

OBJECTIVE: Divalproex sodium can interact with many drugs in which combination treatments are used; it can increase plasma concentrations of some drugs by inhibiting metabolism and can increase the free fractions of other medications by displacing them from plasma proteins. The combination of risperidone and divalproex sodium is used to treat the manic phase of bipolar disorder. However, the effect of risperidone on the pharmacokinetics of valproate has not previously been systematically studied. The aims of this study were to determine the effect of repeated doses of oral risperidone on the pharmacokinetics of valproate in subjects stabilised on divalproex sodium and to document the safety of this combination. STUDY DESIGN: A multicentre, observational, randomised, parallel group, single-blind, placebo-controlled drug interaction study. PATIENTS: Twenty-two patients with bipolar disorder, in remission, were studied. METHODS: All subjects were treated with divalproex sodium 1000 mg/day monotherapy on days 1-14. Thereafter, subjects continued to take divalproex sodium for days 15-28; they also received adjunctive treatment with either placebo (n = 11) or risperidone (n = 11) 2mg once daily on days 15 and 16, and 4 mg once daily on days 17-28. Serial blood sampling was performed throughout to determine the plasma concentrations of valproate, risperidone and 9-hydroxy-risperidone. RESULTS: On analysis, steady-state pharmacokinetic parameters (peak plasma concentrations [C(max)], time to C(max,) area under the concentration-time curve) of valproate were of the same order of magnitude on day 14 (monotherapy) and day 28 (valproate plus risperidone or placebo), with no period effect. The parameters on day 28 were similar in the risperidone and placebo treatment groups, showing that risperidone, as adjunctive treatment, had no influence on the steady-state pharmacokinetics of valproate. Although there were more adverse events reported in the risperidone group compared with the placebo group (ten vs seven, respectively), none of them were serious or necessitated withdrawal. No clinically relevant changes in laboratory parameters, vital signs or ECG-tracings were observed in either group. CONCLUSION: These results indicate that adjunctive risperidone treatment had no influence on the steady-state pharmacokinetics of valproate and this combination was safe and well tolerated.

Determination of total fat in milk- and soy-based infant formula powder by supercritical fluid extraction.

Commercially available simple benchtop systems using CO2 supercritical fluid extraction (SFE) eliminate expensive organic solvent disposal problems and offer potential to meet a demand for rapid, accurate high-volume gravimetric determinations of total fat content of infant formula powders. A Data Quality Objectives (DQOs) approach was used to evaluate the performance characteristics of instrumental SFE extraction for determination of total gravimetric fat in infant formula. The established DQOs included the following: ACCURACY: Correct values were obtained for a suitable reference material, SRM 1846 Infant Formula [National Institute of Standards and Technology (NIST), Gaithersburg, MD]. RUGGEDNESS: Variables were defined as (1) extraction time (35 min optimum); (2) ratio of sample size to diatomaceous earth support material (1 g sample/2 g support); (3) ratio of distilled water to alcohol (50% isopropanol optimum for both milk- and soy-based infant formula samples); (4) extraction flow rate was 3-3.5 mL/min optimum. PRECISION: Relative standard deviations of multiple determinations fell within the Horwitz limits of acceptability of < or = 2.8% at the level of analyte determined (0.34-2.5% obtained). SCOPE OF APPLICABILITY: Includes milk- and soy-based infant formula powders. Research data were obtained by use of a commercially available fat analyzer. Samples of the SRM, 2 commercial milk-based and 3 commercial soy-based infant formula products were distributed to 2 additional collaborating laboratories. Very good agreement was obtained among the submitting and collaborating laboratories for these samples. The use of clearly defined DQOs to establish method performance characteristics, along with the commercially available reference material, provided the mechanism for verification and validation of analytical methodology.

Determination of niacin in infant formula by solid-phase extraction/liquid chromatography: peer-verified method performance-interlaboratory validation.

This paper reports the results of the interlaboratory peer validation study of AOAC Peer-Verified Method (PVM) 1:2,000 for the determination of niacin in infant formula by solid-phase extraction/liquid chromatography. We have used a Data Quality Objectives (DQO) approach to address not only method variability and robustness but also accuracy of data through the use of an appropriate reference material in conjunction with the interlaboratory validation study. Our DQO included the following: (1) statistical agreement of analytical results and quantitative recovery between 2 collaborating laboratories; (2) the repeatability relative standard deviation (RSDr) values and the HORRAT (Horwitz ratio) obtained (1.07), which satisfied the criteria of the Horwitz "limits of acceptability" at the analyte level present; (3) validation of lack of interference; and (4) accuracy agreement within assigned values for a certified reference material. National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1846 Infant Formula, with a certified value of 63.3 +/- 7.6 microg/g for niacin content, was used as a test material for collaborative study and accuracy assessment. Niacin values obtained by the originating laboratory were 59.7 +/- 4.0 microg/g (95% confidence interval [CI] = 1.4 microg/g with a relative standard deviation [RSD] of 6.7%) and by the peer laboratory were 56.6 +/- 6.6 microg/g (95% CI = 4.1 microg/g, with an RSD of 11.7%). Statistical evaluation using the means equivalence test showed that nicotinic acid values obtained by the peer laboratory were equivalent to those values obtained by the originating laboratory. Linear calibration curves and quantitative recovery were obtained. Integration of the PVM process with a readily available certified reference material gives the user confidence in the accuracy of the data generated by the method through traceability to the reference material used.