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QUANTUM NONDEMOLITION MEASUREMENTS IN SYSTEMS ETC.
603
The system equations of motion are (fig. 1)
J~ + 0 9 2 2 -- --
2y(E1 sin (At + 9) + / ~ cos (At + 9)) +fg(t),
The action of the last cascade measuring device is modelled by gedanken state reduction of the system. There are difficulties in treating continuous approximate measurements this way. At the same time, the formal description of those measurements(~6) is cumbersome and nonobvious from the physical point of view. In our model we consider the whole measuring scheme: detector, meter and measuring device (fig. 1). The latter consists of three circulators, a homodyne detector and two degenerate parametric amplifiers (or four wave mixers) with different pump frequencies. According to the ideas of ref. (7-9) the homodyne detector measures the quadrature component of the readout system outgoing radiation, two degenerate parametric amplifiers (or four wave mixers) squeeze in a special way the vacuum fluctuations of the load and the circulators direct the fields into appropriate branches of the system. More concretely, the system outgoing field is directed through circulators C1, C2 and C3 into the load (absorber black-body with zero temperature) and dissipates in it. Zero fluctuations of the load enter through circulators C3 the degenerate parametric amplifier DPA2 with pump frequency 2(~o0+ 2A) and bandwidth A~<~ lzll, then get through circulators C3 and C2 into DPA1 with pump frequency 2~0 and bandwidth A~ ~< ]AI and then get through circulators C2 and C1 into the system.
IL NUOVO CIMENTO
VOL. 10 C, N. 6
Novembre-Dicembre 1987
Quantum Nondemolition Measurements in Systems with Nonstationary Squeezing of Quantum Noise.
V. V. KULAGIN and V. N. RUDENK0 Moscow State University, Department of Physics - 117234 Moscow, USSR
F~ q.1 ~- §
mh~o~)l~,
w h e r e ~ is the duration of external (gravitational) force; m, ~o~ are mass and resonant frequency of the W e b e r detector. Usually only two first cascades of antenna probe oscillator (detector) and readout system (meter) are considered in the quantum mechanics framework (24). (1) V. B. BRAGINSKY,V. P. MITROFANOV,V. I. PANOV: Systems with Small Dissipation, in Russian (Nauka, Moscow, 1981) (English translation: University of Chicago Press, Chicago, Ill., 1985). (2) C. M. CAVES, K. S. THORNE, R. W. P. DREVER, V. D. SANDBERG and M. ZIMMERMANN: Rev. Mod. Phys., 52, 341 (1980). (3) G. J. MILBURN, A. S. LANE and D. F. WALLS: Phys. Rev. A, 27, 2804 (1983). (4) V. V. DODONOV, V. V. KULAGIN, V. I. MAN'KO and V. N. RUDENKO: Experimental Tests of Gravitational Theories, ed. M.S.U., 1987 (to be published).
9 now is the arbitrary phase and we take for simplicity Itll--)0 but EL" Itll = const; EL is the input laser field. A system like (2) was considered earlier with Ebl, Eb2 to be a white stationary noise (1~,13). In our analysis Eb.a. is the squeezed noise with two points of squeezing: 090and ~Oo+ 2A. Let the back-action noise have the form (6) (lo) C. (11) C. (15) A. (~) A.
Eb.a. = Ebl COS090 t +/~b2 sin 090t
= E1 cos 090t +/i~2 sin ommutation relations(l~ The laser field inside the cavity has the form (5) Ep = E0 sin (09vt + 9),
Quantum nondemolition m e a s u r e m e n t s are the only possibility to increase the sensitivity of a W e b e r detector above the standard quantum limit (1,2) (1)
40 - I1 Nuovo Cimento C.
601
602
r
v.v.
= - r o ~t = i t o
KULAGIN and v. N. RUDENKO
1 2w o
12(wo+2A)
Fig. 1 -Gravitational antenna with measuring device. C1, C2, C3 are circulators; DPA1 and DPA2 are the narrow-bandwidth degenerate parametric amplifiers (or four wave mixers); LP is the laser pump; M1 and M2 are fixed and moving mirrors; HD is the homodyne detector; L is the load (absorber).
(5) A. BARCHIELLI, L. LANZ and G. M. PROSPERI: Found. Phys., 13, 779 (1983). (6) A. BARCHIELLI:P h y s . Roy. D, 32, 347 (1985). (7) B. YURKE and J. DENKER: Physica (Utrecht) B, 198, 1359 (1981). (8) B. YURKE and L. R. CORRUCCINI:Phys. Rev. A, 39, 895 (1984). (9) B. YURKE: J. Opt. Soc. Am. B, 2, 732 (1985).
/ ~ + ~E~ + 2~2 cos(At + 9) = 2~fl~b~, (2) E~. + ~fl~2 - 2flJ~ sin (At + 9) = 2~ Eb2, ~~o Eo 21 ' SEo Y=4mnt~' A=09p--oJo,
where E0 is the amplitude of the field inside optical resonator under the action of the ,,laser force, with mirrors fixed; S is the cross-section of the beam; M, 09~are the mass and frequency of the mechanical oscillator; l, 090 are the length and the eigenfrequency of the optical resonator; ~e, is the damping of the optical resonator due to the right mirror (with r0 < 1); )~ is the coordinate operator of the moving mirror; ~opis the frequency of the pump; fg(t) = F(t)/m, F(t) is the external (gravitational) force;/~,/~e and/~b~,/~b2 are the quadrature component operators of the measuring field/~ (3) and back-action field Eb.a. (4)

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light复数形式

light复数形式

light复数形式light的复数形式为lights。

英语单词light有四种词性，作名词时意为“光；光线；光亮；发光体；光源；(尤指)电灯”，作形容词时意为“充满亮光的；明亮的；有自然光的；浅色的；淡色的”，作动词时意为“点燃；点火；开始燃烧；燃起来；照亮”，作副词时意为“轻地；清楚地；轻便地”。

light一、中文释义n. 光；光线；光亮；(具有某种颜色和特性的)光；发光体；光源；(尤指)电灯v. 点燃；点火；开始燃烧；燃起来；照亮；使明亮adj. 充满亮光的；明亮的；有自然光的；浅色的；淡色的；轻的；轻便的；不太重的adv. 轻地；清楚地；轻便地二、词态变化第三人称单数：lights复数：lights现在分词：lighting过去式：lit lighted过去分词：lit lighted比较级：lighter最高级：lightest派生词：lightness n.三、词汇搭配bring light 带来光明clear light 清晰的光线center light 中心光线day light 日光light beacon 灯标light beam 光柱at a light 在交通灯处between the lights 在黄昏,在傍晚light of a lamp 灯光light clothes 轻装so light 清淡的light a fire 生火light on〔upon〕偶然发现,偶然获得……light out 突然发出light the stove 点燃炉子light the street 照亮街道light in weight 重量轻light on one&#39;s feet 脚步轻快very light 非常轻的light work 轻活四、双语例句1.Than the light leading to yesterday. 总有指引向昨天的明亮的光。

2.I want something in light color.我要浅色的。

light的过去式和用法例句

light的过去式和用法例句

light的过去式和用法例句light做动词有点燃;变亮;照亮等意思，那么你知道light的过去式是什么吗?下面小编为大家带来的light的过去式和用法例句，供大家参考学习!light的过去式和其他时态：过去式: lit过去分词: lit现在分词: lightinglight的用法：light的用法1：light用作动词时,其意思是点火生火点燃,指为照明或取暖而点蜡烛或生炉子;light还可指用灯或蜡烛等物体来照亮,照明,引申可指使容光焕发。

light的用法2：light既可用作及物动词,也可用作不及物动词。

用作及物动词时,接名词或代词作宾语;用作不及物动词时,主动形式常含有被动意义。

light的用法3：light的过去式和过去分词有两种形式,即lit或lighted。

lit较lighted用得更普遍,但其过去分词用作形容词时,一般用lighted,不用lit。

light的过去式例句：1. Over coffee, she lit a cigarette, her eyes daring him tocomment.喝咖啡时，她点燃了一支烟，用挑衅的眼神看着他，谅他也不敢吭声。

2. The shooting-range is lit from underneath by rows of ruby-red light fittings.射击场被一排排深红色的灯光设备从下面照亮了.3. Campaigners lit scores of bonfires in ceremonies to mark the anniversary.参加运动的人们在各种仪式上点起一垛垛篝火以纪念周年庆典。

4. Charles lit the fuses and they ran for cover.查尔斯点燃了导火索，他们便赶紧四处躲避。

5. The night sky was lit up by flashes of light.一道道灯光照亮了夜空。

light单词讲解

light单词讲解

light单词讲解"Light"是一个常用的英语单词,意思是光线、明亮、亮光、照亮等。

以下是对这个单词的讲解和拓展:1. 含义:"Light"是一个名词,表示光线、明亮、亮光、照亮等。

它可以用来描述物体发出的光线或光线对物体的影响。

例如,“The sun provides us with a lot of light during the day”(太阳在白天为我们提供大量的光线)。

另外,“light”还可以表示精神上的明亮、轻松和愉快,例如“It"s a nice day, and I feel very light”(今天是晴天,我感到非常轻松)。

2. 时间:"Light"是一个短暂而强烈的光源,例如闪电、闪光灯、烟花等。

它还可以用来描述瞬间的、短暂的事件,例如“The news of the tragedy caused a lot of light”(悲剧的消息引起了广泛关注)。

3. 含义的拓展:除了上面提到的含义,"light"还具有其他一些含义,例如:- 光明、明亮的,例如“The sun lightens the sky”(太阳的光线照亮了天空)。

- 启示、启发的,例如“The book of life gives us light”(《生命的启示》给我们带来启示)。

- 轻率、明快的,例如“He is a light-hearted person”(他是一个开朗的人)。

- 轻快、轻松的,例如“A light breeze brings a sense of calm”(轻风带来一种平静的感觉)。

4. 其他用法:除了上述用法,"light"还有许多其他的用法,例如:- 灯、照亮、照明等,例如“The lights are on in the room”(房间里灯亮着)。

- 光、光线、照明等,例如“The sun provides us with a lot of light”(太阳为我们提供大量的光线)。

light和lights的用法

light和lights的用法

light和lights的用法
"Light" 是名词，指的是光线、灯光或光源。

例如：
1. The light from the sun is very bright.
（太阳的光线非常明亮。

）
2. I turned on the light in the room.
（我打开了房间里的灯。

）
3. The lighthouse helps ships navigate through the darkness.
（灯塔帮助船只在黑暗中航行。

）
"Lights" 是"light" 的复数形式，可以表示多个灯或灯光。

例如：
1. The lights in the city look beautiful at night.
（城市的灯光在晚上看起来很漂亮。

）
2. We need to change the light bulbs in these lights.
（我们需要更换这些灯中的灯泡。

）
3. The stage lights were too bright for the performers.
（舞台灯光对表演者来说太亮了。

）
另外，"light" 也可以作为形容词使用，意思是明亮的或轻盈的。

例如：
1. The room is very light and airy.
（房间非常明亮而通风。

）
2. She likes to wear light clothing in the summer. （她喜欢夏天穿轻薄的衣服。

）。