最深层次的物质状态－夸克物最深层次的物质状态－夸克物质质

庄鹏飞庄鹏飞 ((zhuangpf@mail.tsinghua.edu.cnzhuangpf@mail.tsinghua.edu.cn))

● ● 物质的第五态物质的第五态 ● ● QCDQCD 超导与超流超导与超流 ● ● 相对论重离子碰撞相对论重离子碰撞

　　　 　　　 中国科学技术大学，中国科学技术大学， 2012,06,082012,06,08

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物质科学包含物质的结构和状态物质科学包含物质的结构和状态最深层次的结构最深层次的结构 :: 夸克夸克

问题问题 : : 看不见的夸克看不见的夸克 ,, 质量起源质量起源 ,, 真空结构真空结构 真空不知道，动动真空怎么样？真空不知道，动动真空怎么样？

最深层次的状态：？最深层次的状态：？熟悉的物质三态熟悉的物质三态 : : 固态固态 ,, 液态液态 ,, 气态气态 第四态：原子弹爆炸后产生大块的电磁等离子体第四态：原子弹爆炸后产生大块的电磁等离子体猜测 : 是否存在由夸克和胶子组成的色等离子体 (QGP) ？

David J. Gross H. David Politzer Frank Wilczek

2004 2004 诺贝尔物理奖诺贝尔物理奖

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李政道李政道 : : In order to study the question of ‘vacuum’, In order to study the question of ‘vacuum’, we must turn to a different direction: we must turn to a different direction: we should we should investigate some ‘bulk’ phenomena by distributing investigate some ‘bulk’ phenomena by distributing high energy over a relatively large volume.”high energy over a relatively large volume.” --------------- --------------- Rev. Mod. Phys. 47, 267(1975)Rev. Mod. Phys. 47, 267(1975)

from 1897 to present:from 1897 to present: to comprehend the to comprehend the largest, we largest, we need only understand the smallest.need only understand the smallest.

from present to 21st century:from present to 21st century: to know the smallest, to know the smallest, we need we need also the largest!also the largest!

研究夸克物质的意义研究夸克物质的意义

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温度密度效应 温度密度效应 ——>> 波函数重叠 波函数重叠 ——> > 最深层次物质形态 夸克最深层次物质形态 夸克胶子等离子体胶子等离子体 (QGP)(QGP)

相变：体系对称性质的改变相变：体系对称性质的改变

QCD Phase Transitions: QCD Phase Transitions: * deconfinement * deconfinement * chiral restoration * chiral restoration * color s * color superconductivity * pion superconductivity * pion superfluidity * BCS-uperfluidity * BCS-BEC crossover BEC crossover ............

如何产生夸克物质如何产生夸克物质

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related to early universe related to compact stars

related to relativistic heavy ion collisions

粒子物理 , 核物理 , 凝聚态物理 , 宇宙学 , 天体物理 ,……

superconductivitysuperconductivity and and superfluiditysuperfluidity at high density at high density

清华科技园园标清华科技园园标

夸克物质是多学科的交叉领域夸克物质是多学科的交叉领域

12170 2.3 10cT MeV K a strongly coupled quark-gluon plasma even at extremely high temperature !a strongly coupled quark-gluon plasma even at extremely high temperature !

高温强耦合夸克物质理论高温强耦合夸克物质理论 : : Lattice QCDLattice QCD

胶子自相互作用导致跑动耦合常数：高能弱耦合，低能强耦合！ 胶子自相互作用导致跑动耦合常数：高能弱耦合，低能强耦合！ 极高温高密可以用微扰 极高温高密可以用微扰 QCDQCD ，但如何处理强耦合导致的相变？，但如何处理强耦合导致的相变？Lattice QCD !Lattice QCD !

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高密强耦合夸克物质理论：高密强耦合夸克物质理论： QCDQCD 有效模型有效模型 有限重子数密度时有限重子数密度时 Lattice QCDLattice QCD 有技术困难，尚无精确结果。有技术困难，尚无精确结果。

大大 NcNc 极限下的猜测极限下的猜测Lattice QCDLattice QCD 初步结果初步结果

Temperature Effect: vacuum excitation Temperature Effect: vacuum excitation Density Density Effect: vacuum condensation Effect: vacuum condensation

BCS-BEC crossover is a way to understand the running coupling in QCDBCS-BEC crossover is a way to understand the running coupling in QCD

色对称性自发破缺－色超导色对称性自发破缺－色超导 由由 BCSBCS 理论，在理论，在 QEDQED 凝聚态中，两个电子通过交换光子是排斥相互作用，吸凝聚态中，两个电子通过交换光子是排斥相互作用，吸

引相互作用是通过交换集体激发模式－声子来实现的 引相互作用是通过交换集体激发模式－声子来实现的 (( 低温超导低温超导 )) 。。 CooperCooper 对的形对的形成自发破缺了电磁规范对称性，光子获得了质量。成自发破缺了电磁规范对称性，光子获得了质量。

1( )

4a a

QCD q a ai m g A T F F L

1

4

1

4

ca a jk il ik jlki lj

c

cjk il ik jl

c

NT T

N

N

N

第一项在交换初态或末态的两个夸克色指标时是反对称的，吸引相互作用。在单胶子交换的层次就使得两个夸克可以配对，有 Diquark 凝聚，形成色超导 (( 高温超高温超导导 )) 。由于色对称性自发破缺，胶子获得质量。

夸克的色味结构导致丰富的色超导相图夸克的色味结构导致丰富的色超导相图

Frank WilczekFrank Wilczek(2004(2004 诺贝尔奖诺贝尔奖 ): ): 色超导研究的开创者之一色超导研究的开创者之一

色电中性的无能隙色超导态色电中性的无能隙色超导态 黄梅，何联毅，金猛，赵维黄梅，何联毅，金猛，赵维勤，庄：勤，庄： 2003-20122003-2012

稳定的超导态必须是（电，色）荷中性的：稳定的超导态必须是（电，色）荷中性的：

粒子数的差别引起费米面的差别，使得配对的两个费米子不在同一个费米面上，导致粒子数的差别引起费米面的差别，使得配对的两个费米子不在同一个费米面上，导致Breached Pairing Breached Pairing 色超导态，奇怪的中间温度超导态，解决办法之一是引入有总动色超导态，奇怪的中间温度超导态，解决办法之一是引入有总动量的量的 LOFFLOFF 态。态。

0, 0, e e c ci i i i

i i

Q N Q N

考虑色电中性条件后，无能隙色超导迅速成为考虑色电中性条件后，无能隙色超导迅速成为 QCDQCD 相变研究的一个热点。相变研究的一个热点。我们的相关论文被引用我们的相关论文被引用 10001000 多次。多次。

同位旋对称性自发破缺－同位旋对称性自发破缺－ PionPion 超流超流

● ●the Nambu-Jona-Lasinio (NJL) model inspired by the BCS the Nambu-Jona-Lasinio (NJL) model inspired by the BCS t theory describes well the chiral and t theory describes well the chiral and color condensate.color condensate.

● ●we introduced the pion superfluid in the NJL model .we introduced the pion superfluid in the NJL model .

何联毅，姜寅，毛施君，夏涛，金猛，庄：何联毅，姜寅，毛施君，夏涛，金猛，庄： 2005-20122005-2012

2 2

0 0 5NJL iL i m G i

( , ) 2 Im ( , )k D k

BECBEC BCSBCS

Goldstone modeGoldstone modePion superfluid Pion superfluid phase diagramphase diagram

meson spectra functionmeson spectra function

Nambu Nambu 2008 2008 诺贝尔诺贝尔奖奖

FAIR FAIR U+U@Elab = 40A GeV CSR CSR U+U@Elab = 0.6A GeV

RHIC RHIC AuAu+Au@√s = 200A GeVLHC LHC PbPb+Pb@√s = 5.5A TeV

相对论重离子碰撞是在实验室实现夸克胶子等离子体的唯一可能方式相对论重离子碰撞是在实验室实现夸克胶子等离子体的唯一可能方式

RHICRHIC

searching for the quark-gluon plasma through heavy ion searching for the quark-gluon plasma through heavy ion collisions at ALICE, ATLAS and CMS !collisions at ALICE, ATLAS and CMS !

LHC ! LHC ! LHC !LHC ! LHC ! LHC !

●●RHIC and LHC are making little bang like the big bang.RHIC and LHC are making little bang like the big bang.

●●studying properties onstudying properties on the microseconds-old universe the microseconds-old universe that cannot be addressed by any telescope and satellite.that cannot be addressed by any telescope and satellite.

●●The Liquid Quark-Gluon Plasma shares common features The Liquid Quark-Gluon Plasma shares common features with condensed matter, cold atoms and black holes.with condensed matter, cold atoms and black holes.

A Grand OpportunityA Grand Opportunity

　　　　　　　　　　　　　　　　如何知道在重离子碰撞中产生了如何知道在重离子碰撞中产生了 QGPQGP ? ? 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

QGPQGP只能是重离子碰撞的中间态，即使在只能是重离子碰撞的中间态，即使在 RHICRHIC 和和 LHCLHC 产生了产生了 QGPQGP ，，也不能在末态直接观测到，只能通过携带也不能在末态直接观测到，只能通过携带 QGPQGP信号的末态观测量来判断。信号的末态观测量来判断。

QGPQGP 的信号：的信号： Jet quenching: Jet quenching:

喷注在热密物质中损失能量 Collective flow: Collective flow: 体系的膨胀会产生集体流 Strong Strong fluctuations: fluctuations: 在 QCD 临界点附近 Quarkonium Production:Quarkonium Production: 热密物质中有 Debye屏蔽 Electromagnetic Electromagnetic Signals: Signals: 电磁信号是最干净的信号 Strangeness enhancement: Strangeness enhancement: QGP 中奇异夸克成对产生

RHICRHIC 发现了什么？发现了什么？Jet quenchingJet quenching

STAR

models

Jet quenchingJet quenching

Large vLarge v22

NCQ-scalingNCQ-scaling

J/J/ΨΨ suppression suppression

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J/psi Production in a Full Tansport Model J/psi Production in a Full Tansport Model

relativistic hydrodynamics for QGP evolution relativistic hydrodynamics for QGP evolution + transport equation + transport equation for J/psi motion + QCD for J/psi motion + QCD equation of stateequation of state

朱相雷，刘云朋，周凯，陈保义，许怒，庄朱相雷，刘云朋，周凯，陈保义，许怒，庄 2006-20122006-2012

62 GeV

J/J/ψψ Yield at SPS, RHIC and LHC Yield at SPS, RHIC and LHC

The Jpsi Yields at SPS, RHIC and The Jpsi Yields at SPS, RHIC and LHC Have Similar Behavior ! LHC Have Similar Behavior ! Is There a Jpsi Observable Which Is There a Jpsi Observable Which Is Sensitive to the Hot Medium?Is Sensitive to the Hot Medium?

The Jpsi Yields at SPS, RHIC and The Jpsi Yields at SPS, RHIC and LHC Have Similar Behavior ! LHC Have Similar Behavior ! Is There a Jpsi Observable Which Is There a Jpsi Observable Which Is Sensitive to the Hot Medium?Is Sensitive to the Hot Medium?

/

/

1,

<1, /

>1, /

JAA

AA Jc pp

no medium effect

R J supressionN

J enhancement

Transverse Momentum Distribution !Transverse Momentum Distribution !

Data and Our Model PredictionData and Our Model Prediction

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2

2

>1,

1,

1,

t AAAA

t pp

initial production at SPSp

R competition at RHICp

regeneration at LHC

+ equation of state + equation of state (ideal gas or lattice (ideal gas or lattice simulation)simulation)

A Full Transport Approach for Quarkonia in HICA Full Transport Approach for Quarkonia in HIC

●●quarkoniumquarkonium transport equations transport equations

●●initial production , including CNM. initial production , including CNM. 0( , , )f p x t

● ● QGPQGP hydrodynamics hydrodynamics

αα: suppression : suppression ββ: regeneration: regeneration

● ● analytic solution analytic solution

( / , ', )cJ

0, 0T n

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both initial production and regeneration suffer from screening !both initial production and regeneration suffer from screening !

朱相雷，刘云朋，周凯，陈保义，许怒，庄朱相雷，刘云朋，周凯，陈保义，许怒，庄 2006-20122006-2012

Dissociation Cross Section Dissociation Cross Section

( ) / J g Q Q

( , )gp p●● gluon dissociation cross section calculated by OPE gluon dissociation cross section calculated by OPE (Bhanot, Peskin,1999):(Bhanot, Peskin,1999):

●● at finite temperature, we use the classical relationat finite temperature, we use the classical relation2

2

( )( , , ) ( , )

(0)g g

r Tp p T p p

r is calculated through the is calculated through the

Schroedinger equationSchroedinger equation

2 ( )r T

●● regeneration rate is determined by the detailed balanceregeneration rate is determined by the detailed balance

●● J/J/ΨΨ dissociation rate dissociation rate

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RHICRHIC 的实验结果验证了我们的理论预言的实验结果验证了我们的理论预言

QM2011QM2011 FranceFrance

LHCLHC 将测量我们预言的非零椭圆流将测量我们预言的非零椭圆流(ALICE(ALICE 很快将有结果很快将有结果 ))

QM2011QM2011 LHC LHC

RHIC RHIC

LHCLHC 的实验结果验证了我们的理论预言的实验结果验证了我们的理论预言 NN2012NN2012 USAUSA

LHCLHC 的实验结果验证了我们的理论预言的实验结果验证了我们的理论预言 NN2012NN2012 USAUSA

LHCLHC 的实验结果验证了我们的理论预言的实验结果验证了我们的理论预言 NN2012NN2012 USAUSA

LHCLHC 的实验结果验证了我们的理论预言的实验结果验证了我们的理论预言 NN2012NN2012 USAUSA

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Averaged Transverse Momentum Averaged Transverse Momentum

We are waiting for the data from LHC We are waiting for the data from LHC

QM2012QM2012 USAUSA

结论与展望 结论与展望 ●●Lattice QCDLattice QCD 计算表明相变是一个计算表明相变是一个 CrossoverCrossover ，温度为，温度为 170 MeV170 MeV 。 。 ●●RHICRHIC 的相对论重离子碰撞实验发现了产生强耦合夸克胶子等离子体的相对论重离子碰撞实验发现了产生强耦合夸克胶子等离子体的信号。的信号。 ●● 人们希望在人们希望在 LHCLHC 最后抓住夸克胶子等离子体。 最后抓住夸克胶子等离子体。 ●● 高密高密 QCDQCD 超流与超导的理论研究还有困难，和致密星体与中能重离超流与超导的理论研究还有困难，和致密星体与中能重离子碰撞的联系尚不清楚，但表现出与凝聚态和子碰撞的联系尚不清楚，但表现出与凝聚态和 Cold Atom GasCold Atom Gas 相似的相似的性质。性质。

革命尚未成功，同志仍需努力！革命尚未成功，同志仍需努力！

大事物由小事物组成大事物由小事物组成甚至是更小的。甚至是更小的。要想认识最小的要想认识最小的我们也需要知道最大的。我们也需要知道最大的。一切都取决于真空一切都取决于真空无论何时何地。无论何时何地。微观的事物怎能微观的事物怎能与宏观相分离？与宏观相分离？真空其实是一种凝聚真空其实是一种凝聚破坏了和谐。破坏了和谐。如此我们方可洞穿如此我们方可洞穿不对称中的对称。不对称中的对称。

要想认识最小的，需要认识最大的要想认识最小的，需要认识最大的李政道李政道

Columbia UniversityColumbia University ，， New YorkNew York ，， NY 10027NY 10027

Large things are made of small And Large things are made of small And even smaller. To even smaller. To know the smallest We know the smallest We need also the largest need also the largest

All lie in vacuum All lie in vacuum Everywhen and everywhere. Everywhen and everywhere. How can the micro Be How can the micro Be separate from the macro?separate from the macro?

Let vacuum be a condensate Let vacuum be a condensate Violating harmony Violating harmony We can then penetrate We can then penetrate Through asymmetry into symmetryThrough asymmetry into symmetry