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1.
For a homogeneous quantum network of N subsystems with n levels each we consider separable generalized Werner states. A generalized Werner state is defined as a mixture of the totally mixed state and an arbitrary pure state
:
with a mixture coefficient
. For this density operator
to be separable,
will have an upper bound
. Below this bound one should alternatively be able to reproduce
by a mixture of entirely separable input-states. For this purpose we introduce a set of modules, each contributing elementary coherence properties with respect to a generalized coherence vector. Based on these there exists a general step-by-step mixing process for any
. For
being a cat-state it is possible to define an optimal process, which produces states right up to the separability boundary (
).Received: 3 December 2002, Published online: 29 July 2003PACS:
03.65.Ud Entanglement and quantum nonlocality (e.g. EPR paradox, Bells inequalities, GHZ states, etc.) - 03.67.-a Quantum information - 03.65.-w Quantum mechanics 相似文献
2.
Hyperfine structure and isotope shifts in five optical
transitions: 424.5 nm (
–
), 537.2 nm (
–
), 554.5 nm
(
–
), 560.9 nm
(
–
) and 666.0 nm
(
–
)
of Pb II have been measured. As a light source the discharge tube was used.
The hyperfine structure measurements were
performed using metallic isotope 207Pb. For isotope shifts
measurements natural lead was used. The high resolution spectral apparatus consisted of a silver
coated Fabry-Perot etalon and a grating spectrograph combined
with a CCD camera used as a detector. In the analysis of the
spectra a computer simulation technique was used. The hyperfine
structure observations yielded the splitting constants A for
seven levels of Pb II. The isotope shift studies enabled to
separate the mass and the field shifts and to determine values of
changes of the mean square nuclear charge radii. 相似文献
3.
D. Wang J. Qi M. F. Stone O. Nikolayeva B. Hattaway S. D. Gensemer H. Wang W. T. Zemke P. L. Gould E. E. Eyler W. C. Stwalley 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2004,31(2):165-177
We have observed the photoassociative spectra of colliding ultracold 39K and 85Rb atoms to produce KRb* in all eight bound electronic states correlating with the 39K (4s) + 85Rb(5p
1/2 and 5p
3/2) asymptotes. These electronically excited KRb* ultracold molecules are detected after their radiative decay to the metastable triplet (a
state and (in some cases) the singlet (X
ground state. The triplet (a
ultracold molecules are detected by two-photon ionization at 602.5 nm to form KRb + , followed by time-of-flight mass spectroscopy. We are able to assign a majority of the spectrum to three states (2(0 + ), 2(0-), 2(1)) in a lower triad of states with similar C
6 values correlating to the K(4s) + Rb (5p
1/2) asymptote; and to five states in an upper triad of three states (3(0 + ), 3(0-), 3(1)) and a dyad of two states (4(1), 1(2)), with one set of similar C
6 values within the upper triad and a different set of similar C
6 values within the dyad. We are also able to make connection with the short-range spectra of Kasahara et al. [J. Chem. Phys. 111, 8857 (1999)], identifying three of our levels as v = 61, 62 and 63 of the 1
4(1) state they observed. We also argue that ultracold photoassociation to levels between the K(4s) + Rb (5p
3/2) and K(4s) + Rb (5p
1/2) asymptotes may be weakly or strongly predissociated and therefore difficult to observe by ionization of a
(or X
molecules; we do know from Kasahara et al. that levels of the 1
4(1) and 2
5(1) states in the intra-asymptote region are predissociated. A small fraction (
1/3) of the triplet (a
ultracold molecules formed are trapped in the weak magnetic field of our magneto-optical trap (MOT).Received: 22 September 2004, Published online: 23 November 2004PACS:
33.20.Fb Raman and Rayleigh spectra (including optical scattering) - 34.20.Cf Interatomic potentials and forces - 33.80.Ps Optical cooling of molecules; trapping 相似文献
4.
A. Ehresmann W. Kielich L. Werner Ph. V. Demekhin D. V. Omel''yanenko V. L. Sukhorukov K.-H. Schartner H. Schmoranzer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(2):235-246
Dispersed fluorescence from fragments formed after the de-excitation of the
1s-1π* resonances of N*O and NO* has been
measured in the spectral range of 118–142 nm. This range is dominated by
lines of atomic nitrogen and oxygen fragments and by the
bands in the NO+ ion which result from the participator Auger decay of the 1s-1π* resonances.
Ab-initio calculations of the transition probabilities between vibrational
levels during the reaction NO
N*O
⇒ NO
were used to explain the observed intensity dependence for the
fluorescence bands on the exciting-photon energy across
the resonances and on both v′ and v′′
vibrational quantum numbers. The multiplet structure of the 1s-1π* resonance and lifetime vibrational interference explain the observed exciting-photon energy dependence of the
fluorescence
intensity. A strong spin-orbit coupling between singlet and triplet states
of NO+ is proposed to reduce additional cascade population of the
state via radiative transitions from the
and
states and to explain
remaining differences between measured and calculated integral fluorescence
intensities. 相似文献
5.
A pair
of interacting Kerr oscillators treated as a master coupler sending chaotic or hyperchaotic signals to its slave copy
is considered. We synchronize a with A and b with B through two communication channels
and
. The effect of synchronization is non-simultaneous, the pairs
and
have different times of synchronization. It is possible to synchronize an individual pair, for example,
when its communication channel
is turned off, provided that the second channel for the pair
is turned on. The resulted synchronization is termed induced. The efficiencies of the presented synchronization precesses are studied.Received: 20 February 2003, Published online: 29 April 2003PACS:
05.45.Xt Synchronizations; coupled oscillators - 05.45.Pq Numerical simulations of chaotic systems - 42.65.Sf Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatio-temporal dynamics 相似文献
6.
J. Kurpeta A. Plochocki A. N. Andreyev J. Äystö A. De Smet H. De Witte A.-H. Evensen V. Fedoseyev S. Franchoo M. Górska H. Grawe M. Huhta M. Huyse Z. Janas A. Jokinen M. Karny E. Kugler W. Kurcewicz U. Köster J. Lettry A. Nieminen K. Partes M. Ramdhane H. L. Ravn K. Rykaczewski J. Szerypo K. Van de Vel P. Van Duppen L. Weissman G. Walter A. Wöhr 《The European Physical Journal A - Hadrons and Nuclei》2003,18(1):31-37
A new high-spin isomer in 215Bi, with a half-life of 36.9(6) s, has been identified at the PSB-ISOLDE on-line mass separator using the pulsed-release technique combined with the element selective RILIS source. A decay scheme of
Bi was constructed and complemented with the low-spinstructure observed in
Bi decay. The population of a cascade on top of the
level in 215Poprovides evidence for Gamow-Teller
-decay of the high-spin 215Bi isomer.Received: 3 March 2003, Revised: 10 June 2003, Published online: 9 October 2003PACS:
23.20.Lv
transitions and level energies - 27.80.+w
- 29.30.Kv X- and
-ray spectroscopyV. Fedoseyev: Present address: ISOLDE, CERN-PPE, CH-1211, Geneva 23, Switzerland.M. Górska: Present address: GSI, Darmstadt, D-64220, Germany.M. Huhta: Present address: Nokia, Tampere, Finland. 相似文献
7.
M. Z.M. Kamali K. Ratnavelu Y. Zhou 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(2):267-279
The recent theoretical work by Bartlett et al. [J. Phys. B 38, L95 (2005)] and the latest measurements on the reduced Stokes parameters
,
and
for 54.4 eV electron impact excitation of the 2p state atomic hydrogen by Williams and Mikosza [J. Phys. B 39, 4113 (2006)] has motivated the present work. A coupled-channel-optical calculation with 9 and 12 atomic states supplemented
with the continuum optical potentials for the stronger coupling channels has been performed. The calculated n = 2 and n =
3 differential cross sections and the reduced Stokes parameters are comparable with the state-of-the art calculations. There is closer agreement between the present calculations and the experimental measurements for the reduced
Stokes parameters
and
in the n = 2p excitation at 54.4 eV. The present CCO calculations also display good accord with the limited experimental
data for the reduced Stokes parameters in the n=3p excitation. 相似文献
8.
S. H. Li C. Wang J. S. Liu X. X. Wang R. X. Li G. Q. Ni Z. Z. Xu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,34(1-3):215-218
Using time-of-flight spectrometry, the interaction of intense femtosecond
laser pulses with argon clusters has been studied by measuring the energy
and yield of emitted ions. With two different supersonic nozzles, the
dependence of average ion energy
on cluster size
in a large range of
has been measured. The experimental results indicate that
when the cluster size
, the average ion
energy
Coulomb explosion is the
dominant expansion mechanism. Beyond this size, the average ion energy gets
saturated gradually, the clusters exhibit a mixed Coulomb-hydrodynamic
expansion behavior. We also find that with the increasing gas backing
pressure, there is a maximum ion yield, the ion yield decreases as the gas
backing pressure is further increased. 相似文献
9.
Gyürky Gy. Fülöp Zs. Somorjai E. Kiss G. Rolfs C. 《The European Physical Journal A - Hadrons and Nuclei》2004,20(2):355-358
The absolute strengths of the
keV resonance in the
reaction and of the
keV resonance in the
reaction have been measured to
meV and
meV, respectively, in good agreement with previous values. These resonances can be used to measure the absolute acceptance of the recoil separator ERNA to a precision of about 10%.Received: 12 December 2003, Revised: 10 February 2004, Published online: 3 August 2004PACS:
24.30.-v Resonance reactions - 25.40.Lw Radiative capture - 26.20. + f Hydrostatic stellar nucleosynthesis 相似文献
10.
production in
interactions has been detected via its decays into
,K
+
K
-
K
+
K
- and
in the data taken with the DELPHI detector at LEP1 and LEP2 energies. The two-photon radiative width averaged over all observed decay channels is
= 13.9
2.0 (stat.)
1.4(syst.)
2.7 (BR) keV. No direct decay channel
has been observed. An upper limit
< 5.5 keV at 95% confidence level has been evaluated for this decay mode.Received: 3 July 2003, Published online: 7 November 2003 相似文献
11.
Isomeric states in 210-215Ra have been populated by the decay of the compound nuclei 216,220Ra produced in irradiations of 204,208Pb with 12C at
MeV. Published values for
-ray energies and half-lives were confirmed for
Ra. Our data for
Ra agree with the
-energies and the half-life measured at the RITU separator, University of Jyväskylä (Finland). Its decay pattern is complex. Two series of
-rays of
keV and
keV were observed. A half-life of
s was measured. The isomeric state is attributed to an 8 + state at E
* = 2053.8keV. A previously unknown isomeric state was assigned to
Ra. It has a half-life of (
)
and it decays by emission of
-rays with energies of 396.1keV and 802.0keV. It is attributed to a 13/2 + state at E
* = 1198.1 keV.PACS:
23.60. + e
decay - 27.90. + b
相似文献
12.
The H Collaboration 《The European Physical Journal C - Particles and Fields》2003,29(4):497-513
Inclusive jet cross sections are measured in photoproduction at HERA using the H1 detector. The data sample of
events in the kinematic range of photon virtualities
and photon-proton centre-of-mass energies
represents an integrated luminosity of
. Jets are defined using the inclusive
algorithm. Single- and multi-differential cross sections are measured as functions of jet transverse energy ET jet and pseudorapidity
in the domain
and
. The cross sections are found to be in good agreement with next-to-leading order perturbative QCD calculations corrected for fragmentation and underlying event effects. The cross section differential in ET jet, which varies by six orders of magnitude over the measured range, is compared with similar distributions from
colliders at equal and higher energies.Received: 24 February 2003, Revised: 26 May 2003, Published online: 11 July 2003 相似文献
13.
The three-photon ionization in Ca from
S0 ground state is studied. The two-photon process is a near -- resonance process with one of the following bound states: 4s4d
1D2, 4p
P2, 4s6s
1S0, 4
D2 and 4
S0 while the third photon reach either directly the continuum or one of the autoionizing states. The succession of bound states as well as the transitions above the ionization limit are discussed. The dynamics of the multiphoton excitation processes is also discussed and radiative decay of 4
S0 Ca state with two-photon excitation as well as (the measured) decay times of the Ca autoionizing states using the proper line profiles for different quantum numbers has been determined.Received: 29 September 2003, Published online: 18 May 2004PACS:
32.70.-n Intensities and shapes of atomic spectral lines - 32.70.Cs Oscillator strengths, lifetimes, transition moments - 32.80.Fb Photoionization of atoms and ions - 32.80.Rm Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states) 相似文献
14.
Measurements of on-shell ZZ production are described, using data from the DELPHI experiment at LEP in e
+
e
- collisions at centre-of-mass energies between 183 and 209 GeV, corresponding to an integrated luminosity of about 665 pb-1. Results obtained in each of the final states
,
,
,
,
, l
+
l
-
l
+
l
-, and
(with
) are presented. The measured production cross-sections are consistent with the Standard Model expectations. These results update and supersede those already published at 183 and 189 GeV.Received: 3 March 2002, Revised: 28 May 2003, Published online: 19 September 2003 相似文献
15.
Bouchiat M.-A. Guéna J. Lintz M. 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2004,28(3):331-349
A pump-probe atomic parity violation (APV) experiment performed in a longitudinal electric field
, has the advantage of providing a signal which breaks mirror symmetry but preserves cylindrical symmetry of the set-up, i.e. this signal remains invariant when the pump and probe linear polarizations are simultaneously rotated about their common direction of propagation. The excited vapor acts on the probe beam as a linear dichroic amplifier, imprinting a very specific signature on the detected signal. Our differential polarimeter is oriented to yield a null result unless a chirality of some kind is acting on the excited atoms. Ideally, only the APV (
-odd) and the calibration (
-even) signals should participate in such a chiral atomic response, a situation highly favourable to sensitive detection of a tiny effect. In the present work, we give a thorough analysis of possible undesirable defects such as spurious transverse fields or misalignments, which may spoil the ideal configuration and generate a chiral response leading to possible systematics. We study a possible way to get rid of such defects by performing global rotations of the experiment by incremental angular steps
, leaving both stray fields and misalignments unaltered. Our analysis shows that at least two defects are necessary for the
-odd polarimeter output to be affected; a
modulation in the global rotations reveals the transverse nature of the defects. The harmful systematic effects are those which subsist after we average over four configurations obtained by successive rotations of 45
. They require the presence of a stray transverse electric field. By doing auxiliary atomic measurements made in known, applied, magnetic fields which amplify the systematic effect, it is possible to measure the transverse E-field and to minimize it. Transverse magnetic fields must also be carefully compensated following a similar procedure. We discuss the feasibility of reducing the systematic uncertainty below the one percent level. We also propose statistical correlation tests as diagnoses of the aforementioned systematic effects.Received: 19 November 2003, Published online: 19 February 2004PACS:
32.80.Ys Weak-interaction effects in atoms - 32.60. + i Zeeman and Stark effects - 33.55.Fi Other magnetooptical and electrooptical effects - 42.25.Lc Birefringence 相似文献
16.
The production rates and substructure of jets have been studied in charged current deep inelastic e
+
p scattering for Q
2 > 200 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 110.5 pb-1. Inclusive jet cross sections are presented for jets with transverse energies
GeV and pseudorapidities in the range
. Dijet cross sections are presented for events with a jet having
GeV and a second jet having
GeV. Measurements of the mean subjet multiplicity,
, of the inclusive jet sample are presented. Predictions based on parton-shower Monte Carlo models and next-to-leading-order QCD calculations are compared to the measurements. The value of
, determined from
at
for jets with
GeV, is
. The mean subjet multiplicity as a function of Q
2 is found to be consistent with that measured in NC DIS.Received: 5 June 2003, Published online: 10 October 2003 相似文献
17.
The very recently observed D*sJ(2463) meson is described as a
bound state in a unitarised meson model, owing its existence to the strong OZI-allowed
coupling to the nearby S-wave
threshold. By the same non-perturbative mechanism, the narrow axial-vector Ds1(2536) resonance shows up as a quasi-bound-state partner embedded in the
continuum. With the same model and parameters, it is also shown that the preliminary broad 1 + D1(2400) resonance and the established narrow 1 + D1(2420) may be similar
partners, as a result of the strong OZI-allowed
coupling to the nearby S-wave
threshold. The continuum bound states D1(2420) and Ds1(2536) are found to be mixtures of 33%
and 67%
, whereas their partners D1(2400) and D*sJ(2463) have more or less the opposite
-state content, but additionally with some
or
admixture, respectively. The employed mechanism also reproduces the ratio of the KL-KS mass difference and the KS width, by describing KL as a bound state embedded in the
continuum. The models results for
states containing one b quark are also discussed.Received: 7 June 2003, Revised: 20 October 2003, Published online: 18 December 2003PACS:
12.40.Yx, 14.40.Aq, 14.40.Lb, 13.25.Es, 13.25.Ft, 13.75.Lb 相似文献
18.
X. Z. Cai C. Zhong W. Q. Shen Y. G. Ma H. Y. Zhang Y. B. Wei J. G. Chen W. Guo K. Wang G. L. Ma X. F. Zhou 《The European Physical Journal A - Hadrons and Nuclei》2004,20(2):263-267
,
and
have been calculated via the BUU model with soft EOS and 0.8 times of
. The density distribution without any adjustable parameters which comes from the RMF model has been introduced into the BUU calculation to replace the normally used one-parameter square-type distribution. The calculated results can reproduce the experimental data well for both halo- and stable-nuclei-induced reactions. Here
or
is calculated as the difference between
of halo nucleus and core nucleus, by assuming
. It indicates that this assumption works very well at high energy in the BUU calculation. More experimental measurements are necessary to test the validity of this assumption at intermediate energy.Received: 12 June 2003, Revised: 29 September 2003, Published online: 27 April 2004PACS:
24.10.-i Nuclear reaction models and methods - 25.60.Dz Interaction and reaction cross-sections - 25.60.Gc Breakup and momentum distributions - 27.20. + n
相似文献
19.
20.
Surface structures in the Te/Ni(111) system are revealed by using reflection high-energy electron diffraction combined with X-ray and ultraviolet photoelectron spectroscopies. At a 0.33 mono-layer (ML)-Te/Ni(111) surface, a reversible structural phase transition is observed with a transition temperature Tc of 380
C. The diffraction pattern from the low temperature phase is accompanied by streaks. The high and low temperature phases are characterized by
and
rectangle, respectively. The mechanism of the phase transition is explained by the order-disorder transition with a rumpled chain model. Both 0.51 ML- and 0.44 ML-Te/Ni(111) surfaces exhibit the complex diffraction patterns accompanied by diffuse streaks. These surface structures are characterized by the
rectangle and
, respectively. All diffuse streaks obtained at the above surfaces are consistently interpreted in the view of the ill-ordered arrangements of the well-ordered
linear chains. It is shown that the
linear structure is the key in the Te/Ni(111) system.Received: 1 December 2003, Published online: 20 April 2004PACS:
61.14.Hg Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED) - 68.65.-k Low-dimensional, mesoscopic, and nanoscale systems: structure and nonelectronic properties - 64.60.Cn Order-disorder transformations; statistical mechanics of model systems 相似文献