模仿量子纠缠的“伪造态”

Bell不等式是对一个系统的量子本质的最根本的检验．但实验表明,这个检验可以被欺骗． 在1935年,爱因斯坦、波多尔斯基（Podolsky）和罗森（Rosen）共同辩说量子力学并非完备,因为对某个系统进行测量会立即影响另一个系统的波函数,这与信息传输的光速极限相矛盾．若想避免此“鬼魅般的超距作用”,各系统实际蕴含的内容必须比波函数所描述的要多．量子力学也许需要增补,例如通过引入隐变量理论,使得每一次测量仅依赖定域的自由度．     

玻色-爱因斯坦凝聚(BEC)实验及其最新进展

近年来,有关玻色-爱因斯坦凝聚(BEC)的实验研究得到了快速发展,并取得了一系列重大的实验进展。本文重点介绍了玻色-爱因斯坦凝聚的实验结果及其最新进展,主要包括具有正、负散射长度碱金属(7Li,23Na,41K,85Rb,87Rb和133Cs)原子BEC的实现,自旋极化1H原子、亚稳态4He原子和具有2个价电子的174Yb稀土原子BEC的实现,全光型BEC和微阱BEC乃至低维BEC的实现,甚至分子BEC和费米原子对的凝聚以及超冷BEC凝聚体的应用等。     

捕捉引力波

 一、足够精确的牛顿引力理论在宏观物理世界中,引力是一种主要的作用。太阳东升西坠,地球四季交替,海水潮涨潮落,众多自然现象都受到引力的支配。1687年,牛顿在前人的研究基础上,导出了万有引力定律。利用万有引力定律可以圆满地解释哥白尼的学说和开普勒的行星运动三定律。牛顿引力理论的精彩之处还有准确地预言了海王星和冥王星的存在,指导天文学家成功地发现了这两颗太阳行星。按牛顿的引力理论,两物体间的引力作用是瞬间完成的。但爱因斯坦认为,光速是任何作用的极限速度,因此引力作用不可能在瞬间实现。1905年,爱因斯坦发表著名的历史文献《论动体的电动力学》,建立了狭义相对论。在以后     

玻色—爱因斯坦凝聚(BEC)实验及其最新进展

近年来,有关玻色-爱因斯坦凝聚(BEC)的实验研究得到了快速发展,并取得了一系列重大的实验进展。本文重点介绍了玻色-爱因斯坦凝聚的实验结果及其最新进展,主要包括具有正、负散射长度碱金属(7Li,23Na,41K,85Rb,87Rb和133Cs)原子BEC的实现,自旋极化1H原子、亚稳态4He原子和具有2个价电子的174Yb稀土原子BEC的实现,全光型BEC和微阱BEC乃至低维BEC的实现,甚至分子BEC和费米原子对的凝聚以及超冷BEC凝聚体的应用等。     

超快激光可在半导体上激起“量子液滴”

正以下效果图显示了显微镜下超快红色激光脉冲在砷化镓半导体上激起的"量子液滴"。每滴"液滴"中的电子和空穴以液态模式环状排列,其周围则是等离子体。美国天体物理联合研究实验室的物理学家与德国马尔堡大学的理论学家合作,发现了一类新的准粒子:他们利用超快激光,让半导体内部的多个电子和     

“超快光学”专题征文通知

正当今,由于化学、生物、材料等学科的研究已深入到纳米、分子和原子尺度,在这个层次上绝大多数现象都是超快过程,需要有超高时间、空间分辨能力的测试手段,即信息的超快速获取手段,才能开展研究。以高速摄影和超短脉冲激光为代表的信息的超快速获取是当前信息科学的前沿,在信息、材料与高能量密度物理等领域中具有强烈的渗透性和带动性。     

用BEC泡测量微力

美国莱斯大学的Satyan Bhongale和罗斯·阿莫斯国家实验室的Eddy Timmermans提出了一种用超冷原子凝聚的BEC (Bose-Einstein condensation,玻色-爱因斯坦凝聚)"气泡"测量极微小力的方法,目前他们已经展开相关实验.实验方案中的"气泡"是由一种超冷原子气作为核心,在外面包上一层另一种超冷原子制成.     

Equivalence Postulate and Quantum Origin of Gravitation

We suggest that quantum mechanics and gravity are intimately related. In particular, we investigate the quantum Hamilton–Jacobi equation in the case of two free particles and show that the quantum potential, which is attractive, may generate the gravitational potential. The investigation, related to the formulation of quantum mechanics based on the equivalence postulate, is based on the analysis of the reduced action. A consequence of this approach is that the quantum potential is always non-trivial even in the case of the free particle. It plays the role of intrinsic energy and may in fact be at the origin of fundamental interactions. We pursue this idea, by making a preliminary investigation of whether there exists a set of solutions for which the quantum potential can be expressed with a gravitational potential leading term which alone would remain in the limit 0. A number of questions are raised for further investigation.     

Gravitation, the Quantum and Bohr's Correspondence Principle

The black hole combines in some sense both thehydrogen atom and the black-bodyradiation problems of quantum gravity. Thisanalogy suggests that black-hole quantization may be thekey to a quantum theory of gravity. During the last twenty-fiveyears evidence has been mounting that black-hole surfacearea is indeed quantized, with uniformally spaced areaeigenvalues. There is, however, no general agreement on the spacing of the levels. In thisessay we use Bohr's correspondence principle to providethis missing link. We conclude that the fundamental areaunit is 4h ln 3. This is the unique spacing consistent both with the area-entropythermodynamic relation for black holes, withBoltzmann-Einstein formula in statistical physics andwith Bohr's correspondence principle.     

On Some Processes of Quantum Gravitation (Radiative Corrections)

Within the framework of the quantum theory of interactions of nonpoint (smeared out) particles [1], the radiative corrections due to gravitational interactions are examined. The gravitational masses are calculated for a photon, a graviton, and some other particles together with the renormalized gravitational interaction constant K(m) depending on the interacting particle mass m. The approximate character of the equivalence principle is confirmed.     

Perturbations Can Enhance Quantum Search

In general, a quantum algorithm wants to avoid decoherence or perturbation, since such factors may cause errors in the algorithm. We show that some perturbations to the generalized quantum search Hamiltonian can reduce the running time and enhance the success probability. We also provide the narrow bound to the perturbation which can be beneficial to quantum search. In addition, we show that the error induced by a perturbation on the Farhi and Gutmann Hamiltonian can be corrected by another perturbation.