论量子超光速性

Discussions of the Quantum Superluminality

A.Einstein对量子力学(QM)的反对态度从1926年开始显露,1935年与B.Podolsky、N.Rosen联合发表论文时达到顶点,而EPR论文后来是从反面促进了科学的发展。该文以狭义相对论(SR)为思想基础,而SR和EPR都否定超光速的可能性。但QM允许超光速存在,并与研究超光速的前提即QM非局域性一致。1985年John Bell说,Bell不等式是分析EPR推论的产物,该推论说在EPR文章条件下不应存在超距作用;但那些条件导致QM预示的奇特相关性。Aspect实验的结果是在预料之中的,因为QM从未错过,现在知道即使在苛刻的条件下它也不会错;可以肯定实验证明了Einstein的观念站不住脚。Bell认为在进退两难的处境下可以回到Lorentz和Poincarè,他们的以太是一种特惠参考系,在其中事物可以比光快。Bell指出正是EPR给出了超光速的预期。……1992年以来有多个超光速实验成功的报道,有的以量子隧穿为基础,有的利用经典物理现象(如消失波、反常色散)。而在2008年,D.Salart等用处于纠缠态的相距18km的2个光子完成的实验证明其相互作用的速度比光速大一万倍以上,为104c～107c;可以说此实验对有关EPR的长期争论作了结论。过去25年来,量子超光速性是笔者的主要研究课题之一。1985年我们提出了量子势垒的等效电路模型;1991年我们最早指出截止波导中消失波模有负相速(vp<0)和负群速(vg<0)现象,笔者的专著《截止波导理论导论》获全国优秀科技著作奖。2003年我们用同轴光子晶体进行实验并观测到阻带中的超光速群速,为(1.5～2.4)c。2005年我们提出广义信息速度(General Information Velocity,GIV)和在2010年提出量子超光速性(Quantum Super-luminality,QS)两个概念,并建议改造现有的高能粒子加速器以寻找和发现超光速奇异电子。本文则较深刻地讨论了QS的若干问题,涉及微观粒子的速度定义、EPR思维与超光速研究的关系、量子纠缠态作用速度、量子隧穿的超光速性、负波速、Casimir效应的超光速性。文中指出Sommerfeld-Brillouin波速理论的意义和不足,用实验例说明量子光学(QO)方法与经典物理概念结合运用是重要的。自2000年以来的负群速实验常以某金属(如铯、钾、铷)的原子蒸汽状态作为受试对象,充分利用激光的高科技特性和手段,从而使之成为具有典型QO特征的现代物理实验,因而极不同于经典性质的物理实验。负群速不仅是超光速的特殊形态,而且普遍具有下述特征:输入脉冲进入媒质前,出口处即呈现输出脉冲峰,因而与经典因果性不同。虽然关于QS的知识和发现是丰富的和生动的,并且极有启发性,但它并不正面和直接地回答"物质、能量、信息能否以超光速传送"的问题。设计巧妙而有说服力的实验仍是科学家们的基本任务。

A.Einstein held an opposite attitude towards Quantum Mechanics（QM）,which first appeared in 1926 and reached the top in 1935 when he,together with B.Podolsky,N.Rosen published the EPR thesis and it promotes science development in an opposite side.The EPR thesis is based on Special Relativity（SR）.Both SR and EPR deny the possibility of faster-than-light.But QM allows the existence of faster-than-light,agreeing to non-locality of QM is the premise of researching in faster-than light.In 1965,during the interview John Bell confided that his unequality was the outcome of EPR thinking,which denied ultra-space effect under EPR thesis,conditions resulted in quite peculiar correlations that QM predicted.The results of Aspect’s experiments were within expectation that QM has never been wrong now and will not in the future despite of strict requirements.Undoubtedly,the experiments proved that Einstein’s ideas didn’t hold water.In Bell’s opinion,to get rid of the difficulties after the announcement of the Aspect’s experiments,it intends to go back to Lorentz and Poincarè,and assume that ether existed as a referential system in which matters went faster than light.Bell repeatedly pointed out that be wanted to go back to ether because EPR had predicted there was something faster than light in the background.…… Since 1992,it is reported that there have been many successful faster than light experiments.Some of them are based on quantum tunneling effect;some are based on classic physical phenomena such as evanescent waves,anomalous dispersion.And in 2008,D.Salart et.al.performed a experiment using entangled photons between two villages separated by 18km.In conclusion,the speed of the influence of quantum entanglement would have to exceed than of light by at least four orders of magnitude,i.e.10 4 c ～ 10 7 c.Anyway,this experiment was the summation of discussions about the EPR thesis for a long time.For the past 25 years Quantum Superluminality was one subject of my chief study.In 1985,we proposed the model of quantum potential barrier equivalent circuit.In 1991,we first indicated that there could be the wave velocity v p 0 and v g 0 in the evanescent waves mode of the waveguide below cut off and the book ＂An Introduction to the Theory of waveguide Below Cut-off ＂made me get the First National Scientific and Technology Book Award of China.Moreover,in 2003 we through an experiment in the coaxial photonic crystal,a superluminal group velocity of（1.5 ～ 2.4） c are observed in the stop-band of frequency.In 2005,we suggested the term of General Information Velocity（GIV）;and in 2010,we suggested the term of Quantum Superluminality（QS）,and also suggested remodel the existing accelerator to discover the superluminal strange electron.Now,this paper discusses some problems of Quantum Superluminality profoundly,such as the velocity definition of the microscopic particles,the relation between the EPR thinking and the faster-than-light research,the interaction speed of the quantum entangle-state,superluminality of the quantum tunneling,the negative wave velocity,QS of the Casimir effect.We show that the unite of Quantum Optics（QO） and classical physical sujects are becoming more important.Since 2000,the negative group velocity experiments are always employing some atomic metal（such as Cs、Ka、Rb） vapor for tests.It make full use of the latest achievement in laser science and technology,then it was modern physical experiment in QO,not the classical physical experiment.The negative group velocity not only the special situation of faster-than-light,but also has the features： the exiting pulse’s peak can appear to exit the medium before the peak of the input pulse enters.So it was different that of classical causality.Although that knowledges and discovers of QS are widen and lively,then it greatly inspired us;but it is not the immediate conclusion that answers some questions about the possibility of material,energy and information according to faster-than-light propagation.To design the ingenious and convincing superluminal experiments are also basic task of scientists.