🙇🏻 🚇 ❌ 站在科学的最前沿：arxiv.org文章分析 👩‍🎓 🧛🏼 👨🏽‍🚒

我的专长是凝聚态物理。当然，在沉浸其中的过程中，需要学习许多科学文章，但是解析至少一篇文章可能要花费很多时间。每月在cond-mat部分的arxiv上发表超过一千篇文章。在某些情况下，许多研究人员，尤其是初学者，对他们的科学领域没有全面的认识。本文中描述的工具总结了科学论文数据库的内容，旨在加快文献工作。

值得一提的是，我们正在发明一辆自行车，只有我们的自行车可以免费骑行（付费类似物的价格如此低俗，以至于不能接受表示）。
该自行车将以Python组装， Gensim用于主题建模， Plot.ly用于可视化。本文结尾是指向Jupyter笔记本电脑和GitHub的链接。

该作品的原始资料是科学文章的注释和文字。如果前者以“现成的” XML格式提供给我们，则需要将文章的PDF文件转换为txt，由于此过程，文本中会残留大量“垃圾”，因此需要认真清理。

样本注释

<?xml version="1.0" encoding="UTF-8"?> <feed xmlns="http://www.w3.org/2005/Atom"> <link href="http://arxiv.org/api/query?search_query%3D%26id_list%3D1706.09062%26start%3D0%26max_results%3D10" rel="self" type="application/atom+xml"/> <title type="html">ArXiv Query: search_query=&id_list=1706.09062&start=0&max_results=10</title> <id>http://arxiv.org/api/ECEwpFhuO79sa+LzMzx6/iStFak</id> <updated>2018-05-01T00:00:00-04:00</updated> <opensearch:totalResults xmlns:opensearch="http://a9.com/-/spec/opensearch/1.1/">1</opensearch:totalResults> <opensearch:startIndex xmlns:opensearch="http://a9.com/-/spec/opensearch/1.1/">0</opensearch:startIndex> <opensearch:itemsPerPage xmlns:opensearch="http://a9.com/-/spec/opensearch/1.1/">10</opensearch:itemsPerPage> <entry> <id>http://arxiv.org/abs/1706.09062v1</id> <updated>2017-06-27T22:03:24Z</updated> <published>2017-06-27T22:03:24Z</published> <title>On Bose-Einstein condensation and superfluidity of trapped photons with coordinate-dependent mass and interactions</title> <summary> The condensate density profile of trapped two-dimensional gas of photons in an optical microcavity, filled by a dye solution, is analyzed taking into account a coordinate-dependent effective mass of cavity photons and photon-photon coupling parameter. The profiles for the densities of the superfluid and normal phases of trapped photons in the different regions of the system at the fixed temperature are analyzed. The radial dependencies of local mean-field phase transition temperature $T_c^0 (r)$ and local Kosterlitz-Thouless transition temperature $T_c (r)$ for trapped microcavity photons are obtained. The coordinate dependence of cavity photon effective mass and photon-photon coupling parameter is important for the mirrors of smaller radius with the high trapping frequency, which provides BEC and superfluidity for smaller critical number of photons at the same temperature. We discuss a possibility of an experimental study of the density profiles for the normal and superfluid components in the system under consideration. </summary> <author> <name>Oleg L. Berman</name> </author> <author> <name>Roman Ya. Kezerashvili</name> </author> <author> <name>Yurii E. Lozovik</name> </author> <arxiv:doi xmlns:arxiv="http://arxiv.org/schemas/atom">10.1364/JOSAB.34.001649</arxiv:doi> <link title="doi" href="http://dx.doi.org/10.1364/JOSAB.34.001649" rel="related"/> <arxiv:comment xmlns:arxiv="http://arxiv.org/schemas/atom">14 page 5, figures</arxiv:comment> <link href="http://arxiv.org/abs/1706.09062v1" rel="alternate" type="text/html"/> <link title="pdf" href="http://arxiv.org/pdf/1706.09062v1" rel="related" type="application/pdf"/> <arxiv:primary_category xmlns:arxiv="http://arxiv.org/schemas/atom" term="cond-mat.mes-hall" scheme="http://arxiv.org/schemas/atom"/> <category term="cond-mat.mes-hall" scheme="http://arxiv.org/schemas/atom"/> </entry> </feed>

范例文字

On Bose-Einstein condensation and super¬‚uidity of trapped photons with

coordinate-dependent mass and interactions

Oleg L. Berman1,2, Roman Ya. Kezerashvili1,2, and Yurii E. Lozovik3,4

1Physics Department, New York City College of Technology, The City University of New York,

2The Graduate School and University Center, The City University of New York,

Brooklyn, NY 11201, USA

3Institute of Spectroscopy, Russian Academy of Sciences, 142190 Troitsk, Moscow, Russia

4National Research University Higher School of Economics, Moscow, Russia

New York, NY 10016, USA

(Dated: June 29, 2017)

The condensate density pro¬Ѓle of trapped two-dimensional gas of photons in an optical micro-
cavity, ¬Ѓlled by a dye solution, is analyzed taking into account a coordinate-dependent e¬Ђective
mass of cavity photons and photon-photon coupling parameter. The pro¬Ѓles for the densities of the
super¬‚uid and normal phases of trapped photons in the di¬Ђerent regions of the system at the ¬Ѓxed
temperature are analyzed. The radial dependencies of local mean-¬Ѓeld phase transition temperature
T 0
c (r) and local Kosterlitz-Thouless transition temperature Tc(r) for trapped microcavity photons
are obtained. The coordinate dependence of cavity photon e¬Ђective mass and photon-photon cou-
pling parameter is important for the mirrors of smaller radius with the high trapping frequency,
which provides BEC and super¬‚uidity for smaller critical number of photons at the same temper-
ature. We discuss a possibility of an experimental study of the density pro¬Ѓles for the normal and
super¬‚uid components in the system under consideration.

Key words: Photons in a microcavity; Bose-Einstein condensation of photons; super¬‚uidity of

photons.

PACS numbers: 03.75.Hh, 42.55.Mv, 67.85.Bc, 67.85.Hj

I.

INTRODUCTION

When a system of bosons is cooled to low temperatures, a substantial fraction of the particles spontaneously occupy
the single lowest energy quantum state. This phenomenon is known as Bose-Einstein condensation (BEC) and its
occurs in many-particle systems of bosons with masses m and temperature T when the de Broglie wavelength of the
Bose particle exceeds the mean interparticle distance [1]. The most remarkable consequence of BEC is that there
should be a temperature below which a ¬Ѓnite fraction of all the bosons ЂњcondenseЂќ into the same one-particle state
with macroscopic properties described by a single condensate wavefunction, promoting quantum physics to classical
time- and length scales.

Most recently, the observations at room temperature of the BEC of two-dimensional photon gas con¬Ѓned in an optical
microcavity, formed by spherical mirrors and ¬Ѓlled by a dye solution, were reported [2Ђ“5]. The interaction between
microcavity photons is achieved through the interaction of the photons with the non-linear media of a microcavity,
¬Ѓlled by a dye solution. While the main contribution to the interaction in the experiment, reported in Ref. 2, is
thermooptic, it is not a contact interaction.
It is known that BEC for bosons can exist without particle-particle
interactions [6] (see Ref. 1 for the details), but at least the interactions with the surrounding media are necessary to
achieve thermodynamical equilibrium. For photon BEC it can be achieved by interaction with incoherent phonons [7].
The in¬‚uence of interactions on condensate-number ¬‚uctuations in a BEC of microcavity photons was studied in Ref. 8.
The kinetics of photon thermalization and condensation was analyzed in Refs. 9Ђ“11. The kinetics of trapped photon
gas in a microcavity, ¬Ѓlled by a dye solution, was studied, and, a crossover between driven-dissipative system laser
dynamics and a thermalized Bose-Einstein condensation of photons was observed [12].

In previous theoretical studies the equation of motion for a BEC of photons con¬Ѓned by the axially symmetrical
trap in a microcavity was obtained.
It was assumed that the changes of the cavity width are much smaller than
the width of the trap [13]. This assumption results in the coordinate-independent e¬Ђective photon mass mph and
photon-photon coupling parameter g. In this Paper, we study the local super¬‚uid and normal density pro¬Ѓles for
trapped two-dimensional gas of photons with the coordinate-dependent e¬Ђective mass and photon-photon coupling
parameter in a an optical microcavity, ¬Ѓlled by a dye solution. We propose the approach to study the local BEC
and local super¬‚uidity of cavity photon gas in the framework of local density approximation (LDA) in the traps of
larger size without the assumption, that total changes of the cavity width are much smaller than the size of the trap.
In this case, we study the e¬Ђects of coordinate-dependent e¬Ђective mass and photon-photon coupling parameter on
the super¬‚uid and normal density pro¬Ѓles as well as the pro¬Ѓles of the local temperature of the phase transition for
trapped cavity photons. Such approach is useful for the mirrors of smaller radius with the high trapping frequency,

2

which provide BEC and super¬‚uidity for smaller critical number of photons at the same temperature.

The paper is organized in the following way.

In Sec. II, we obtain the condensate density pro¬Ѓle for trapped
microcavity photon BEC with locally variable mass and interactions. The expression for the number of particles in a
condensate is analyzed in Sec. III. In Sec. IV, the dependence of the condensate parameters on the geometry of the
trap is discussed. In Sec. V, we study the collective excitation spectrum and super¬‚uidity of 2D weakly-interacting
Bose gas of cavity photons. The results of our calculations are discussed in Sec. VI. The proposed experiment for
measuring the distribution of the local density of a photon BEC is described in Sec. VII. The conclusions follow in
Sec. VIII.

II. THE CONDENSATE DENSITY PROFILE

While at ¬Ѓnite temperatures there is no true BEC in any in¬Ѓnite untrapped two-dimensional (2D) system, a true
2D BEC quantum phase transition can be obtained in the presence of a con¬Ѓning potential [14, 15]. In an in¬Ѓnite
translationally invariant two-dimensional system, without a trap, super¬‚uidity occurs via a Kosterlitz€'Thouless
super¬‚uid (KTS) phase transition [16]. While KTS phase transition occurs in systems, characterized by thermal
equilibrium, it survives in a dissipative highly nonequilibrium system driven into a steady state [17].

The trap for the cavity photons can be formed by the concave spherical mirrors of the microcavity, that provide
the axial symmetry for a trapped gas of photons. Thus the transverse (along xy plane of the cavity) con¬Ѓnement
of photons can be achieved by using an optical microcavity with a variable width. Let us introduce the frame of
reference, where z€'axis is directed along the axis of cavity mirrors, and (x, y) plane is perpendicular to this axis. The
energy spectrum E(k) for small wave vectors k of photons, con¬Ѓned in z direction in an ideal microcavity with the
coordinate-dependent width L(r), is given by [2]

E(k) =

ЇhЂcњn

...

[23] L. Onsager, ЂњStatistical Hydrodynamics,Ђќ Nuovo Cimento Suppl. 6, 279 (1949).
[24] RP Feynman, ЂњApplication of Quantum Mechanics to Liquid Helium,Ђќ Prog. Low Temp. Phys. 1, 17 (1955).
[25] PC Hohenberg and PC Martin, ЂњMicroscopic Theory of Super¬‚uid Helium,Ђќ Ann. Phys. 34, 291 (1965).
[26] G. Blatter, MY FeigelЂman, YB Geshkenbein, AI Larkin, and VM Vinokur, ЂњVortices in high-temperature super-

conductors,Ђќ Rev. Mod. Phys. 66, 1125 (1994).

[27] NS Voronova and Yu. E. Lozovik, ЂњExcitons in cores of exciton-polariton vortices,Ђќ Phys. Rev. B 86, 195305 (2012);
NS Voronova, AA Elistratov, and Yu. E. Lozovik, ЂњDetuning-Controlled Internal Oscillations in an Exciton-Polariton
Condensate,Ђќ Phys. Rev. Lett. 115, 186402 (2015) .

[28] A. Gri¬ѓn, ЂњConserving and gapless approximations for an inhomogeneous Bose gas at ¬Ѓnite temperatures,Ђќ Phys. Rev. B

53, 9341 (1996).

[29] AA Abrikosov, LP Gorkov and IE Dzyaloshinski, Methods of Quantum Field Theory in Statistical Physics (Prentice-

Hall, Englewood Cli¬Ђs. NJ, 1963).

[30] OL Berman, Yu. E. Lozovik, and DW Snoke, ЂњTheory of Bose-Einstein condensation and super¬‚uidity of two-

dimensional polaritons in an in-plane harmonic potential,Ђќ Phys. Rev. B 77, 155317 (2008).

[31] OL Berman, R. Ya. Kezerashvili, and K. Ziegler, ЂњSuper¬‚uidity and collective properties of excitonic polaritons in gapped

graphene in a microcavityЂќ, Phys. Rev. B 86, 235404 (2012).

[32] A. Amo, J. Lefr`ere, S. Pigeon, C. Adrados, C. Ciuti, I. Carusotto, R. Houdrґe, E. Giacobino, and A. Bramati, ЂњSuper¬‚uidity

of polaritons in semiconductor microcavities,Ђќ Nature Physics 5, 805 (2009).

[33] JP Fernґandez and WJ Mullin, ЂњThe Two-Dimensional Bose€'Einstein Condensate,Ђќ J. Low. Temp. Phys. 128, 233

从注释中，我们仅需要有关作者和文章小节的信息。

下面作为示例，我们考虑了2017年cond-mat部分中的一系列文章。所描述的所有内容都很容易在其他任何部分进行复制。

开始研究文本的最简单方法是列出我们感兴趣的关键字列表，并计算其中出现文章的比例。

例如，让我们评估份额与2010年相比的变化。

2017年和2010年的股份差异。 （注：因研究物质的拓扑阶段而获得2016年诺贝尔物理学奖）

此外，根据文本的内容，我们建立了word2vec模型（为了可视化，最好采用20个单词的更大窗口）。对于每个键，我们获取N个最近的邻居，并借助t-SNE来计算其2D坐标。我们看一下关键字之间的关系：

关键字及其附属词云，N = 100。 第N个邻居越远，单词突出显示的越多。 相关对：石墨烯+半导体，量子位+点，拓扑+霍尔，玻色+凝聚

在arxiv上，每个部分都有小节。我们找出在哪些部分中找到关键字：

解码 cond-mat 的细分名称

上面介绍了如何使用您要手动撰写的一组关键字，但是某些主题可能已被跳过。让我们建立一个LDA模型并查看以下主题：

对于每个主题，我们都会获得与之对应的文章列表：

如您所知，在阅读文章时，研究链接总是很有用的。我们可以收集有关它们的一些信息吗？我们可以！让我们看一下文本的结尾。

尾巴

[23] L. Onsager, ЂњStatistical Hydrodynamics,Ђќ Nuovo Cimento Suppl. 6, 279 (1949).
[24] RP Feynman, ЂњApplication of Quantum Mechanics to Liquid Helium,Ђќ Prog. Low Temp. Phys. 1, 17 (1955).
[25] PC Hohenberg and PC Martin, ЂњMicroscopic Theory of Super¬‚uid Helium,Ђќ Ann. Phys. 34, 291 (1965).
[26] G. Blatter, MY FeigelЂman, YB Geshkenbein, AI Larkin, and VM Vinokur, ЂњVortices in high-temperature super-

conductors,Ђќ Rev. Mod. Phys. 66, 1125 (1994).

[27] NS Voronova and Yu. E. Lozovik, ЂњExcitons in cores of exciton-polariton vortices,Ђќ Phys. Rev. B 86, 195305 (2012);
NS Voronova, AA Elistratov, and Yu. E. Lozovik, ЂњDetuning-Controlled Internal Oscillations in an Exciton-Polariton
Condensate,Ђќ Phys. Rev. Lett. 115, 186402 (2015) .

[28] A. Gri¬ѓn, ЂњConserving and gapless approximations for an inhomogeneous Bose gas at ¬Ѓnite temperatures,Ђќ Phys. Rev. B

53, 9341 (1996).

[29] AA Abrikosov, LP Gorkov and IE Dzyaloshinski, Methods of Quantum Field Theory in Statistical Physics (Prentice-

Hall, Englewood Cli¬Ђs. NJ, 1963).

[30] OL Berman, Yu. E. Lozovik, and DW Snoke, ЂњTheory of Bose-Einstein condensation and super¬‚uidity of two-

dimensional polaritons in an in-plane harmonic potential,Ђќ Phys. Rev. B 77, 155317 (2008).

[31] OL Berman, R. Ya. Kezerashvili, and K. Ziegler, ЂњSuper¬‚uidity and collective properties of excitonic polaritons in gapped

graphene in a microcavityЂќ, Phys. Rev. B 86, 235404 (2012).

[32] A. Amo, J. Lefr`ere, S. Pigeon, C. Adrados, C. Ciuti, I. Carusotto, R. Houdrґe, E. Giacobino, and A. Bramati, ЂњSuper¬‚uidity

of polaritons in semiconductor microcavities,Ђќ Nature Physics 5, 805 (2009).

[33] JP Fernґandez and WJ Mullin, ЂњThe Two-Dimensional Bose€'Einstein Condensate,Ђќ J. Low. Temp. Phys. 128, 233

PDF Converter可以很好地处理带有书目的部分。这意味着可以使用一些正则表达式来检索链接。结果，我们获得了经常引用的必读文章列表。

在Google学术搜索中查看以下链接：

列出每个小节中最活跃的作者-我们从注释中提取并计算author标签的内容。特定作者发表的文章数量是可以理解但不可靠的特征，可以用共同作者数量的中位数来补充（请参阅笔记本）。

来自MES-HALL的作者无与伦比：他们的平均工作速度每周超过一篇文章...

最后，我们估算小节的比例：

演示笔记本电脑： cond-mat.17 ， astro-ph.17 ， cs.17 ， math.17
Github ： ilovescience

站在科学的最前沿：arxiv.org文章分析

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