星期三, 十一月 22, 2006

Zanjani2003 电和磁场中里德堡原子的实验研究

博士论文
通过实验研究在静电场和磁场下的高里德堡态原子。

HIGH RESOLUTION MICROWAVE SPECTROSCOPY OF ULTRA COLD RYDBERG ATOMS AS A PROBE OF ELECTRIC AND MAGNETIC FIELDS
by
Parisa Bohlouli Zanjani

A thesis presented to the University of Waterloo in fulfillment of the thesis requirement for the degree of Master of Science in Physics
Waterloo, Ontario, 2003
Parisa Bohlouli Zanjani, 2003

Lai2001 强磁场中的物质

综述强磁场中的物质,包括原子,分子,凝聚态等。也是以天文为背景的。

Matter in strong magnetic fields
Dong Lai
REVIEWS OF MODERN PHYSICS, VOLUME 73:629, JULY 2001

Turbiner2006 强磁场下的单电子分子 4

基于对单中子星1E1207.4 − 5209的谱的观测,指出在强磁场中的单电子系统中,氢原子不是能量最低的,因此氢分子离子等是可能稳定存在的。

One-electron molecular systems in a strong magnetic field
Alexander V. Turbiner∗,1, Juan Carlos López Vieyra
Physics Reports 424 (2006) 309 – 396

Harding2006 中子星强磁场物理 4

综述了中子星表面强磁场的影响以及观测应用。天文背景浓。

Physics of strongly magnetized neutron stars

Alice K Harding and Dong Lai

Rep. Prog. Phys. 69 (2006) 2631–2708

Lieb 1992 中子星表面的重原子

考虑强磁场,原子序数,将计算分为5个区,分别近似计算。

Heavy atoms in the strong magnetic field of a Neutron Star
Lieb et al
PRL, 1992, 69, 749

Kravchenko1996 强磁场下氢原子的精确解

计算均匀磁场下的氢原子

Highly Accurate Solution for a Hydrogen Atom in a Uniform Magnetic Field

Yu. P. Kravchenko,1,2 M. A. Liberman,1,2 and B. Johansson1
The highly accurate series solution for a hydrogen atom in a uniform magnetic field of arbitrary strength is obtained. It is derived in the form of a power series in two variables, the radius and the sine of the cone angle, with explicit recurrent relations for the coefficients of the power series. As an illustration, a brief list of energy values with accuracy 10212 hartree for the magnetic field
0 < B < 4000 and pictures of selected anticrossings in the chaotic region of the spectrum are presented.

VOLUME 77, NUMBER 4 PHYS I CAL RE V I EW LETTERS 22 JULY 1996

Heyl1998 强磁场中少电子原子分子的计算

计算了氢原子,氦原子和氢分子离子的波函数等。

PHYSICAL REVIEW A VOLUME 58, NUMBER 5 NOVEMBER 1998

Hydrogen and helium atoms and molecules in an intense magnetic field

Jeremy S. Heyl* and Lars Hernquist

We calculate the atomic structure of hydrogen and helium atoms and molecules in an intense magnetic field analytically and numerically with a judiciously chosen basis.

Kravchenko1996 任意磁场下氢原子的精确解

主要是给出了氢原子的各能级随磁场的变化。

氢原子的哈密顿量:
Exact solution for a hydrogen atom in a magnetic field of arbitrary strength
Yu. P. Kravchenko and M. A. Liberman

An exact solution describing the quantum states of a hydrogen atom in a homogeneous magnetic field of arbitrary strength is obtained in the form of a power series in the radial variable with coefficients being polynomials in the sine of the polar angle. Energy levels and wave functions for the ground state and for several excited states are calculated exactly for the magnetic field varying in the range 0< B/(m^2e^3c/h^3) < 4000.

Braun2002 强磁场中原子的能级计算

二维密度泛函计算强磁场中的原子能级。包括He,C,N和He的一些激发态。
与multi-Landau-channel Hartree-Fock calculations方法做了比较。

说明进一步的计算还没有做,也很困难。

Density-functional calculations in a two-dimensional finite-element basis for atoms in very strong magnetic fields: Energy values
Author M. Braun
PHYSICAL REVIEW A, VOLUME 65, 033415

Kondratyev2001 强磁场对原子核质量的影响

在磁场达到10^16G以上之后,会影响到原子核的质量。(属于 原子核的内容)

THE ASTROPHYSICAL JOURNAL, 546:1137È1148, 2001 January 10

MAGNETIC FIELD EFFECT ON MASSES OF ATOMIC NUCLEI
V. N. KONDRATYEV,1 TOSHIKI MARUYAMA, AND SATOSHI CHIBA
Advanced Science Research Center, Japan Atomic Energy Research Institute, 2-4 Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 Japan

星期二, 十一月 21, 2006

Potekhin1997 强磁场下氢原子的电离

不采用绝热近似(绝热近似是什么?忘了)计算了氢原子的电离。是以朗道能级为基础的。

Astron. Astrophys. 317, 618 629 (1997)

Ionization of the hydrogen atom in strong magnetic elds
Beyond the adiabatic approximation
A.Y. Potekhin1;2;3, G.G. Pavlov4;1, and J.Ventura2;3

Miller1991 强磁场中原子的计算

用Hartree-Fock方法计算了多个原子的能级和振子强度。自认为此方法可以扩展,计算更高序数的原子。

Title:
Atoms in very strong magnetic fields
Authors:
Miller, M. C.; Neuhauser, D.
Affiliation:
AA(Illinois, University, Urbana), AB(California Institute of Technology, Pasadena)
Publication:
Royal Astronomical Society, Monthly Notices (ISSN 0035-8711), vol. 253, Nov. 1, 1991, p. 107-122. (MNRAS Homepage)
Publication Date:
11/1991

Kossl1988 密度泛函求强磁场下原子的基态

密度泛函求强磁场下原子的基态以及类氦原子的基态和结合能。


1988, Kossl, AA, 205, 347

Wunner1987 白矮星表面氢原子的能级和波函数

给出了强磁场 白矮星表面氢原子的能级和波函数的部分数据。

Wunner 1987, Ap&SS, 131, 595

Williams1985 中子星表面的类氢原子

主要是介绍方法。强磁场和相对论效应。特别关注了一下类氢铁离子。

ApJ, 1985, 289, 782

Wedahra1983 强磁场中类氢原子的标度计算

1983年就已经开始这类计算了,并发表在ApJ上。不过当时不是 直接的数值计算,而主要是解析推导,解析近似。

星期一, 十一月 20, 2006

Pavlov2005 强磁场中的一价氦原子

计算了强磁场中的一价氦原子的能级。

这篇文章至少说明结合天文背景的原子能谱计算还有大量可以做的工作。

The Astrophysical Journal, 635:L61–L64, 2005 December 10

ONCE-IONIZED HELIUM IN SUPERSTRONG MAGNETIC FIELDS
George G. Pavlov1 and Victor G. Bezchastnov2,3
Received 2005 April 15; accepted 2005 November 1; published 2005 November 30
ABSTRACT
It is generally believed that magnetic fields of some neutron stars, the so-called magnetars, are enormously strong,
up to 1014–1015 G. Recent investigations have shown that the atmospheres of magnetars are possibly composed of
helium. We calculate the structure and bound-bound radiative transitions of the He ion in superstrong fields,
including the effects caused by the coupling of the ion’s internal degrees of freedom to its center-of-mass motion.
We show that He in superstrong magnetic fields can produce spectral lines with energies of up to ≈3 keV, and it
may be responsible for absorption features detected recently in the soft X-ray spectra of several radio-quiet isolated
neutron stars. Quantization of the ion’s motion across a magnetic field results in a fine structure of spectral lines,
with a typical spacing of tens of electron volts in magnetar-scale fields. It also gives rise to ion cyclotron transitions,
whose energies and oscillator strengths depend on the state of the bound ion. The bound-ion cyclotron lines of He
can be observed in the UV-optical range at G, and they get into the soft X-ray B  1013 range at B  1014 G.
Subject headings: atomic processes—line: formation—stars: individual (1E 1207.45209)—
stars: magnetic fields—stars: neutron—X-rays: stars

Bhattacharyya2006 中子星表面原子谱线的形状

中子星表面的原子谱线不仅要受到磁场的影响,还会受到因旋转导致的多普勒效应,还有狭义和广义相对论效应。对于弱磁场的种子星,磁场的影响甚至 可以忽略。

The Astrophysical Journal, 644:1085–1089, 2006 June 20

THE SHAPES OF ATOMIC LINES FROM THE SURFACES
OF WEAKLY MAGNETIC ROTATING NEUTRON STARS AND THEIR IMPLICATIONS
Sudip Bhattacharyya,1 M. Coleman Miller,1, 2 and Frederick K. Lamb3, 4
Received 2004 December 6; accepted 2006 March 3
ABSTRACT
Motivated by the report by Cottam et al. of iron resonance scattering lines in the spectra of thermonuclear bursts
from EXO 0748676, we have investigated the information about neutron star structure and the geometry of the
emission region that can be obtained by analyzing the profiles of atomic lines formed at the surface of the star. We
have calculated the detailed profiles of such lines, taking into account the star’s spin and the full effects of special and
general relativity, including light bending and frame dragging. We discuss the line shapes produced by rotational
Doppler broadening and magnetic splitting of atomic lines for the spin rates and magnetic fields expected in neutron
stars in low-mass X-ray binary systems.We show that narrow lines are possible even for rapidly spinning stars if the
emission region or the line of sight are close to the spin axis. For most neutron stars in low-mass systems, magnetic
splitting is too small to obscure the effects of special and general relativity.We show that the ratio of the star’s mass to
its equatorial radius can be determined to within 5% using atomic line profiles, even if the lines are broad and skewed.
This is the precision required to constrain strongly the equation of state of neutron star matter.We show further that if
the radius and latitude of emission are known to 5%–10% accuracy, then frame dragging has a potentially detectable
effect on the profiles of atomic lines formed at the stellar surface.
Subject headinggs: equation of state — line: profiles — relativity — stars: neutron — stars: rotation —
X-rays: stars

Sanwal2002 孤立中子星1E 1207.4-5209的X射线谱

1E 1207.4-5209是超新星遗迹PKS 1209-51/52中的一颗孤立中子星,文章给了Chandra对它X射线的谱的观测。在0.7和1.4keV上有明显的吸收。一个可能的解释是一价氦原子在强磁场中的跃迁。

The Astrophysical Journal, 574:L61–L64, 2002 July 20

DISCOVERY OF ABSORPTION FEATURES IN THE X-RAY SPECTRUM OF AN ISOLATED NEUTRON STAR
D. Sanwal,1 G. G. Pavlov,1 V. E. Zavlin,2 and M. A. Teter1
Received 2002 April 19; accepted 2002 June 17; published 2002 June 24
ABSTRACT
We observed 1E 1207.45209, a neutron star in the center of the supernova remnant PKS 120951/52, with
the ACIS detector aboard the Chandra X-Ray Observatory and detected two absorption features in the source
spectrum. The features are centered near 0.7 and 1.4 keV; their equivalent widths are about 0.1 keV. We discuss
various possible interpretations of the absorption features and exclude some of them. A likely interpretation is
that the features are associated with atomic transitions of once-ionized helium in the neutron star atmosphere
with a strong magnetic field. The first clear detection of absorption features in the spectrum of an isolated neutron
star provides an opportunity to measure the mass-to-radius ratio and to constrain the equation of state of the
superdense matter.
Subject headings: pulsars: individual (1E 1207.45209)—stars: neutron—
supernovae: individual (PKS 120951/52)—X-rays: stars

Cottam2006 中子星中引力红移后的谱

文章对X射线双星EXO 0748-676的X射线暴做了观测,辨认出了一些铁线,发现引力红移值在0.35.

Gravitationally redshifted absorption lines in the X-ray burst spectra of a neutron star

Authors: J. Cottam (1), F. Paerels (2), M. Mendez (3) ((1) NASA/GSFC, (2) Columbia, (3) SNON)
Comments: Published in Nature (Nov 7, 2002)
Journal-ref: Nature 420 (2002) 51-54
The fundamental properties of neutron stars provide a direct test of the equation of state of cold nuclear matter, a relationship between pressure and density that is determined by the physics of the strong interactions between the particles that constitute the star. The most straightforward method of determining these properties is by measuring the gravitational redshift of spectral lines produced in the neutron star photosphere. The equation of state implies a mass-radius relation, while a measurement of the gravitational redshift at the surface of a neutron star provides a direct constraint on the mass-to-radius ratio. Here we report the discovery of signficant absorption lines in the spectra of 28 bursts of the low-mass X-ray binary EXO 0748-676. We identify the most signficant features with the Fe XXVI and XXV n=2-3 and O VIII n=1-2 transitions, all with a redshift of z=0.35, identical within small uncertainties for the respective transitions. For an astrophysically plausible range of masses (M ~ 1.3-2.0 M_solar), this value is completely consistent with models of neutron stars composed of normal nuclear matter, while it excludes some models in which the neutron stars are made of more exotic matter.

Burwitz2002 孤立中子星RX J1856.5-3754的热谱观测

由Chamdra和XMM-Newton观测。此文是反面的,认为辐射可以用两个黑体成分拟合,而不是强磁场中的原子谱。



The thermal radiation of the isolated neutron star RX J1856.5-3754 observed with Chandra and XMM-Newton

Authors: V. Burwitz, F. Haberl, R. Neuhaeuser, P. Predehl, J. Truemper, V.E. Zavlin (Max-Planck-Institut fuer extraterrestrische Physik (MPE Garching))
Comments: 6 pages, (including 3 figures) accepted for publication in Astronomy and Astrophysics (A&A)
Journal-ref: Astron.Astrophys. 399 (2003) 1109-1114
We present results of the analysis of data collected in 57-ks XMM-Newton and 505-ks Chandra observations of the nearby ~= 120 pc isolated neutron star RX J1856.5-3754. We confirm most of the statements made by Burwitz et al. (2001) who discussed the original 55-ks Chandra data. Detailed spectral analysis of the combined X-ray and optical data rules out the currently available nonmagnetic light and heavy element neutron star atmosphere (LTE) models with hydrogen, helium, iron and solar compositions. We find that strongly magnetized atmosphere models also are unable to represent the data. The X-ray and optical data show no spectral features and are best fitted with a two-component blackbody model with kT_{bb,X}^{\infty} ~= 63.5 eV and R_{bb,X}^{\infty} ~= 4.4(d/120 pc) km for the hot X-ray emitting region, and kT_{bb,opt}^{\infty}<33>17(d/120 pc) km for the rest of the neutron star surface responsible for the optical flux. The large number of counts collected with XMM-Newton allows us to reduce the upper limit on periodic variation in the X-ray range down to 1.3% (at a 2\sigma confidence level) in the 10^{-3}-50 Hz frequency range. In an attempt to explain this small variability, we discuss an one-component model with kT_{bb}^{\infty} ~= 63 eV and R_{bb}^{\infty} ~= 12.3(d/120 pc) km. This model requires a low radiative efficiency in the X-ray domain, which may be expected if the neutron star has a condensed matter surface.

星期五, 十一月 10, 2006