Squeezing and Spectroscopy of Atoms in a Cavity.

Although an ideal degenerate optical parametric oscillator (DOPO) can generate perfect squeezing at the output of a one-sided optical cavity when operating just below threshold, its intracavity squeezing is limited to less than one-half (50%) of its perfect value. However, when two-level atoms are introduced into the DOPO cavity, the amount of intracavity squeezing can be enhanced, from its maximum value of 50%, to a maximum value of 75% in the good-cavity limit due to the strong interaction between the two-level atoms and the subharmonic field mode. This extra intracavity squeezing is significant in studying spectroscopy of atoms interacting with a squeezed field mode inside an optical cavity.Although an ideal degenerate optical parametric oscillator (DOPO) can generate perfect squeezing at the output of a one-sided optical cavity when operating just below threshold, its intracavity squeezing is limited to less than one-half (50%) of its perfect value. However, when two-level atoms are introduced into the DOPO cavity, the amount of intracavity squeezing can be enhanced, from its maximum value of 50%, to a maximum value of 75% in the good-cavity limit due to the strong interaction between the two-level atoms and the subharmonic field mode. This extra intracavity squeezing is significant in studying spectroscopy of atoms interacting with a squeezed field mode inside an optical cavity.

Physical Review AJan 1, 199413 citations

Spin squeezing via ladder operations on an atomic coherent state

Christopher C. Gerry, Adil Benmoussa

We study the generation of spin squeezing by the repeated action of the angular momentum (Dicke) lowering operator on an atomic coherent state prepared for a collection of $N$ two-level atoms or ions. The atoms or ions of the atomic coherent state are not entangled, but the action of the lowering operator (or similarly of the raising operator) generates entanglement among the atoms, and spin squeezing occurs for some ranges of the relevant parameter. Spin squeezing in a collection of two-level atoms or ions is of importance for precision spectroscopy. We discuss methods by which our spin-squeezed states could be generated in the contexts of cavity QED and trapped ions.We study the generation of spin squeezing by the repeated action of the angular momentum (Dicke) lowering operator on an atomic coherent state prepared for a collection of $N$ two-level atoms or ions. The atoms or ions of the atomic coherent state are not entangled, but the action of the lowering operator (or similarly of the raising operator) generates entanglement among the atoms, and spin squeezing occurs for some ranges of the relevant parameter. Spin squeezing in a collection of two-level atoms or ions is of importance for precision spectroscopy. We discuss methods by which our spin-squeezed states could be generated in the contexts of cavity QED and trapped ions.

Physical Review AJun 30, 20087 citations

Quantum State Spectroscopy of Atom-Cavity Systems

Todd Tilma, R. P. Rundle, Ben Davies +2 more

The Japan Society of Applied PhysicsJul 10, 20190 citations

Free Space Ramsey Spectroscopy in Rubidium with Noise below the Quantum Projection Limit

Benjamin K. Malia, Julián Martínez-Rincón, Yunfan Wu +2 more

We demonstrate the utility of optical cavity generated spin-squeezed states in free space atomic fountain clocks in ensembles of 390 000 ^{87}Rb atoms. Fluorescence imaging, correlated to an initial quantum nondemolition measurement, is used for population spectroscopy after the atoms are released from a confining lattice. For a free fall time of 4 milliseconds, we resolve a single-shot phase sensitivity of 814(61) microradians, which is 5.8(0.6) decibels (dB) below the quantum projection limit. We observe that this squeezing is preserved as the cloud expands to a roughly 200 μm radius and falls roughly 300 μm in free space. Ramsey spectroscopy with 240 000 atoms at a 3.6 ms Ramsey time results in a single-shot fractional frequency stability of 8.4(0.2)×10^{-12}, 3.8(0.2) dB below the quantum projection limit. The sensitivity and stability are limited by the technical noise in the fluorescence detection protocol and the microwave system, respectively.We demonstrate the utility of optical cavity generated spin-squeezed states in free space atomic fountain clocks in ensembles of 390 000 ^{87}Rb atoms. Fluorescence imaging, correlated to an initial quantum nondemolition measurement, is used for population spectroscopy after the atoms are released from a confining lattice. For a free fall time of 4 milliseconds, we resolve a single-shot phase sensitivity of 814(61) microradians, which is 5.8(0.6) decibels (dB) below the quantum projection limit. We observe that this squeezing is preserved as the cloud expands to a roughly 200 μm radius and falls roughly 300 μm in free space. Ramsey spectroscopy with 240 000 atoms at a 3.6 ms Ramsey time results in a single-shot fractional frequency stability of 8.4(0.2)×10^{-12}, 3.8(0.2) dB below the quantum projection limit. The sensitivity and stability are limited by the technical noise in the fluorescence detection protocol and the microwave system, respectively.

arXiv:1912.10218Physical Review LettersJul 24, 202021 citations

Atoms in Cavities and Traps

HERBERT WALTHER

Advances in atomic, molecular, and optical physicsJan 1, 199430 citations

We study the generation of spin squeezing by the repeated action of the angular momentum (Dicke) lowering operator on an atomic coherent state prepared for a collection of

N

two-level atoms or ions. The atoms or ions of the atomic coherent state are not entangled, but the action of the lowering operator (or similarly of the raising operator) generates entanglement among the atoms, and spin squeezing occurs for some ranges of the relevant parameter. Spin squeezing in a collection of two-level atoms or ions is of importance for precision spectroscopy. We discuss methods by which our spin-squeezed states could be generated in the contexts of cavity QED and trapped ions.