Entangled-State Cycles of Atomic Collective-Spin States

Abstract

We study quantum trajectories of collective atomic spin states of $N$ effective two-level atoms driven with laser and cavity fields. We show that interesting ``entangled-state cycles'' arise probabilistically when the (Raman) transition rates between the two atomic levels are set equal. For odd (even) $N$, there are $(N+1)/2$ ($N/2$) possible cycles. During each cycle the $N$-qubit state switches, with each cavity photon emission, between the states $(|N/2,m>\pm |N/2,-m>)/\sqrt{2}$, where $|N/2,m>$ is a Dicke state in a rotated collective basis. The quantum number $m$ ($>0$), which distinguishes the particular cycle, is determined by the photon counting record and varies randomly from one trajectory to the next. For even $N$ it is also possible, under the same conditions, to prepare probabilistically (but in steady state) the Dicke state $|N/2,0>$, i.e., an $N$-qubit state with $N/2$ excitations, which is of particular interest in the context of multipartite entanglement.

10 pages, 9 figures

References in corpus (11)

• Scalable multi-particle entanglement of trapped ions
• Strong atom-field coupling for Bose-Einstein condensates in an optical cavity on a chip
• Proposed realization of the Dicke-model quantum phase transition in an optical cavity QED system
• Detecting Genuine Multipartite Entanglement with Two Local Measurements
• Experimental Observation of Four-Photon Entangled Dicke State with High Fidelity
• Characterizing the entanglement of symmetric many-particle spin-1/2 systems
• Deterministic Dicke state preparation with continuous measurement and control
• Stabilising entanglement by quantum jump-based feedback
• Tavis-Cummings model and collective multi-qubit entanglement in trapped ions
• Generating conditional atomic entanglement by measuring photon number in a single output channel
• Entangled-state cycles from conditional quantum evolution

Cited by in corpus (6)

• Quantum feedback: theory, experiments, and applications
• Entanglement and spin squeezing in non-Hermitian phase transitions
• Generation of pure continuous-variable entangled cluster states of four separate atomic ensembles in a ring cavity
• Extreme spin squeezing in the steady state of a generalized Dicke model
• Continuous variables approach to entanglement creation and processing
• Generation of Spin Cat States in an Engineered Dicke Model