本文選題：超冷里德堡原子　切入點(diǎn)：極性里德堡原子氣體　出處：《山西大學(xué)》2016年博士論文　論文類型：學(xué)位論文

【摘要】：里德堡原子是外層電子被激發(fā)到主量子數(shù)很大n1)的激發(fā)態(tài)原子,具有相互作用強(qiáng)(～n4)、輻射壽命長(zhǎng)(～n3)、極化率大(～n7)等奇特性質(zhì),因而一直受到人們的廣泛關(guān)注。超冷里德堡原子之間由于強(qiáng)的偶極-偶極相互作用產(chǎn)生的偶極阻塞效應(yīng),使里德堡原子成為實(shí)現(xiàn)可控量子邏輯門、量子信息處理、單光子源及多體物理等研究的理想備選介質(zhì),在近年來成為研究的熱點(diǎn)。本文以銫原子為介質(zhì),利用激光冷卻和俘獲技術(shù)在磁光阱中制備了溫度為-100μK、密度為～109cm-3的超冷原子團(tuán)。利用雙光子激發(fā)的方式制備了超冷里德堡原子,利用脈沖場(chǎng)電離法探測(cè)里德堡原子電離后的離子譜。通過原子團(tuán)兩側(cè)的柵極板施加外部電場(chǎng)實(shí)現(xiàn)對(duì)超冷里德堡原子的操控。由于nS里德堡態(tài)具有很小的分?jǐn)?shù)量子虧損,其能級(jí)接近于(n-4)類氫多重態(tài),因此在很小的電場(chǎng)中會(huì)與之形成態(tài)混合以及能級(jí)的回避交叉。本文通過對(duì)外場(chǎng)中里德堡原子斯塔克譜的精密測(cè)量,詳細(xì)研究了nS態(tài)與(n-4)類氫態(tài)的回避交叉。并在此基礎(chǔ)上利用實(shí)驗(yàn)測(cè)量的回避交叉與理論模擬相對(duì)比,提出了一種修正nS態(tài)量子虧損的新方法；此外,通過絕熱地操控外場(chǎng)使初始制備的nS態(tài)原子布居到高-l里德堡斯塔克態(tài),制備了一種高極性的里德堡原子氣；最后,通過精密調(diào)控電場(chǎng)兩次通過同一回避交叉,制備了一種新型里德堡原子干涉儀。具體如下：一.在磁光阱中通過雙光子激發(fā)在外場(chǎng)中精密測(cè)量了49S1/2態(tài)和n=45高-l多重態(tài)形成的三能級(jí)回避交叉離子譜。通過量子模擬比對(duì)實(shí)驗(yàn)中回避交叉測(cè)量的能級(jí)差,對(duì)已有的nS態(tài)量子虧損進(jìn)行了修正。二.通過電場(chǎng)的精密操控,使初始制備的nS態(tài)里德堡原子絕熱地通過回避交叉,制備及探測(cè)了強(qiáng)相互作用下高極性里德原子氣體。初始制備的里德堡原子(～500德拜)絕熱躍遷到高-l斯塔克態(tài),因此獲得了巨大的電偶極矩(～2500德拜)。這些高-l態(tài)原子鑲嵌在其它處于高-|m|斯塔克態(tài)的背景原子中,并與其相互作用,產(chǎn)生m態(tài)混合。這種混合使得這些原子獲得較高的電離域,從能夠通過脈沖場(chǎng)電離法使之與初始態(tài)分離并進(jìn)行探測(cè)。三.通過精細(xì)操控電場(chǎng)兩次通過同一回避交叉,制備了一種新型的里德堡原子干涉儀。原子經(jīng)過回避交叉的絕熱/非絕招過程類似于傳統(tǒng)干涉儀中的分束及合束過程。初始制備的兩個(gè)斯塔克能級(jí)在通過能級(jí)回避交叉的中心時(shí)成為相干疊加態(tài),為這種新型干涉儀的產(chǎn)生提供了基礎(chǔ)。通過傅利葉轉(zhuǎn)換分析測(cè)量原子干涉信號(hào)的頻譜,發(fā)現(xiàn)干涉頻率與斯塔克譜中參與回避交中各能級(jí)之間的能量差相對(duì)應(yīng)。在傳統(tǒng)的光學(xué)激發(fā)手段中,由于躍遷選擇定則(△l=±1)的限制,無(wú)法通過直接激發(fā)使中間態(tài)原子(P態(tài))躍遷到高-l態(tài)。該干涉儀克服了禁戒躍遷的限制,提供了一種測(cè)量斯塔克能譜的新方法。本文的創(chuàng)新之處：1.提出了一種對(duì)nS態(tài)里德堡原子的量子虧損進(jìn)行修正的方法。該方法利用參與回避交叉能級(jí)之間的能量差(～100MHz)來修正,大大地規(guī)避了傳統(tǒng)方法中測(cè)量電離域所帶來的誤差。2.通過外場(chǎng)操控里德堡原子通過回避交叉,制備和探測(cè)了極性里德堡氣體。這種方法只需非常小的電場(chǎng)(～1V/cm)即可使初始態(tài)(～500德拜)獲得巨大的電偶極矩(～2500德拜)。3.通過精密操控電場(chǎng)通過同一回避交叉,制備了一種新型的里德堡原子干涉儀�？衫迷摲椒ㄈヌ綔y(cè)光學(xué)激發(fā)光譜中由于禁戒躍遷而無(wú)法直接激發(fā)的能級(jí)。
[Abstract]:The outer electrons are excited Rydberg atoms to the principal quantum number N1) very excited atoms, with strong interaction (~ N4) radiation, long service life (~ N3), polarization rate (~ N7) and other unique properties, which has attracted much attention. Ultra cold Rydberg atoms due to the strong the dipole dipole interaction of the dipole blocking effect, the Rydberg atoms become controllable quantum logic gates, quantum information processing, an ideal medium of single photon source and many body physics, in recent years has become a hot research topic. Based on the original sub cesium medium in magneto optical trap was prepared by temperature -100 K the use of laser cooling and trapping technology, the density of ~ 109cm-3 ultra cold atoms at ultracold Rydberg atoms by using two-photon excitation method, using pulsed field ionization ion detection of Rydberg atoms ionized by atomic mass spectrum. The gate plate on both sides of the external electric field is applied to realize the control of ultra cold Rydberg atoms. Because nS Rydberg states with fractional quantum loss is small, the level is close to (n-4) hydrogenlike multiplets, so in the field is very small in the formation of mixed state and avoid crossing level with the precise measurement of the Rydberg. In the outer field of Stark spectroscopy, a detailed study of the nS (n-4) state and avoid cross hydrogenic states. Based on the experimental measurement and theoretical simulation of avoided crossing comparison, this paper presents a new method for correction of nS state quantum loss; in addition, in high Rydberg Stark state by nS -l atom manipulation of the initial field insulation cloth preparation, a highly polar Rydberg atom gas preparation; finally, through precise regulation two times through the same electric field to avoid cross, preparation of a new type of Rydberg atom interferometer Instrument. Details are as follows: 1. In a magneto-optical trap in the outfield in precision measurement of three level 49S1/2 state and n=45 high -l multiplet formation avoided crossing ion spectra of the two-photon stimulated by quantum simulation. The comparison experiment in cross measurement to avoid the gap on the existing state of quantum nS loss for correction. Two. The control precision of the electric field, the initial preparation of nS Rydberg atoms adiabatically by avoiding cross, preparation and detection of the strong interaction under high polar gas. Reed atom initially prepared Rydberg atoms (~ 500 Debye) adiabatic transition to high -l Starr g state, thereby achieving great the dipole moment (~ 2500 Debye). These states of -l atoms embedded in other -|m| in the high background of stark state atoms, and their interactions, generating M state mixing. This makes these mixed atomic ionization domain from high, can through the veins The pulsed field ionization method and detection and initial state separation. Three. Through the fine manipulation through the same electric field two times to avoid cross, a new type of Rydberg atom interferometer was prepared by atom. Avoid crossing the adiabatic / non beam process process is similar to the traditional trick in the interferometer. Two stark levels initially prepared in the center of the cross level to avoid a coherent superposition state, provide the basis for this new interferometer. Measurement and analysis of atomic interference signal spectrum by Fu Liye transform, frequency spectrum and stark interference found corresponding to the energy level difference in avoidance between the energy exchange in. The traditional optical excitation method, the selection rule (l= + 1) limit, not by direct excitation of atoms in the middle (P state) transition to high -l state. The interferometer overcomes the limitation of forbidden transition, Provide a new method for measuring the stark spectrum. The innovation of this paper: 1. this paper puts forward the method of modifying a nS Rydberg atom quantum loss. By using this method in avoiding cross level difference between energy (~ 100MHz) to correct, greatly avoid the error brought by.2. measurement of ionization domain the traditional method in the field through the manipulation of Rydberg atoms by avoiding cross, preparation and detection of polar Rydberg gas. Electric field this method only needs very small (~ 1V/cm) can make the initial state (~ 500 Debye) huge dipole moment (~ 2500 Debye).3. by precision control by the same electric field avoid crossing, a new type of Rydberg atom interferometer was prepared. The method can be used to detect the level of optical excitation spectrum due to direct excitation transitions.

【學(xué)位授予單位】：山西大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：O562

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 董慧杰;黃可樹;李昌勇;趙建明;張臨杰;賈鎖堂;;Electric dipole moments of lithium atoms in Rydberg states[J];Chinese Physics B;2014年09期

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本文編號(hào)：1629499