A Single Photon Can Simultaneously Excite Two or More Atoms
Omar Di Stefano2020
Sign up for access to the world's latest research
checkGet notified about relevant papers
checkSave papers to use in your research
checkJoin the discussion with peers
checkTrack your impact
Abstract
We consider two separate atoms interacting with a single-mode optical resonator. When the frequency of the resonator field is twice the atomic transition frequency, we show that there exists a resonant coupling between one photon and two atoms, via intermediate virtual states connected by counter-rotating processes. If the resonator is prepared in its one-photon state, the photon can be jointly absorbed by the two atoms in their ground state which will both reach their excited state with probability close to one. Like ordinary quantum Rabi oscillations, this process is coherent and reversible, so that two atoms in their excited state will undergo a downward transition jointly emitting a single cavity photon. This joint absorption and emission processes can also occur with three atoms. The parameters used to investigate this process correspond to experimentally demonstrated values in circuit quantum electrodynamics systems. PACS numbers: 42.50.Pq, 42.50.Ct, 85.25.Cp, 84.40.Az 1 ar X ...
Related papers
One Photon Can Simultaneously Excite Two or More Atoms
Physical review letters, 2016
We consider two separate atoms interacting with a single-mode optical or microwave resonator. When the frequency of the resonator field is twice the atomic transition frequency, we show that there exists a resonant coupling between one photon and two atoms, via intermediate virtual states connected by counterrotating processes. If the resonator is prepared in its one-photon state, the photon can be jointly absorbed by the two atoms in their ground state which will both reach their excited state with a probability close to one. Like ordinary quantum Rabi oscillations, this process is coherent and reversible, so that two atoms in their excited state will undergo a downward transition jointly emitting a single cavity photon. This joint absorption and emission process can also occur with three atoms. The parameters used to investigate this process correspond to experimentally demonstrated values in circuit quantum electrodynamics systems.
Atoms in distant resonators can jointly absorb a single photon
arXiv (Cornell University), 2019
The coherent nonlinear process where a single photon simultaneously excites two or more two-level systems (qubits) in a single-mode resonator has recently been theoretically predicted [Phys. Rev. Lett. 117, 043601 (2016)]. Here we explore the case where the two qubits are placed in different resonators in an array of two or three weakly coupled resonators. Investigating different setups and excitation schemes, we show that this process can still occur with a probability approaching one under specific conditions. The obtained results provide interesting insights into subtle causality issues underlying the simultaneous excitation processes of qubits placed in distant resonators.
On the analogy between a single atom and an optical resonator
Laser Physics, 2010
A single atom in free space can have a strong influence on a light beam and a single photon can have a strong effect on a single atom in free space. Regarding this interaction, two conceptually different questions can be asked: can a single atom fully absorb a single photon and can a single atom fully reflect a light beam. The conditions for achieving the full effect in either case are different. Here we discuss related questions in the context of an optical resonator. When shaping a laser pulse properly it will be fully absorbed by an optical resonator, i.e., no light will be reflected and all the pulse energy will accumulate inside the resonator before it starts leaking out. We show in detail that in this case the temporal pulse shape has to match the time-reversed pulse obtained by the cavity's free decay. On the other hand a resonator, made of highly reflecting mirrors which normally reflect a large portion of any incident light, may fully transmit the light, as long as the light is narrow band and resonant with the cavity. The analogy is the single atom -normally letting most of the light passwhich under special conditions may fully reflect the incident light beam. Using this analogy we are able to study the effects of practical experimental limitations in the atom-photon coupling, such as finite pulses, bandwidths, and solid angle coverage, and to use the optical resonator as a test bed for the implementation of the quantum experiment. * Electronic address: [email protected] †
Single photon transfer controlled by excitation phase in a two-atom cavity system
Journal of Physics B: Atomic, Molecular and Optical Physics
We investigate the quantum interference effects of single photon transfer in two-atom cavity system caused by external excitation phase. In the proposed system, two identical atoms (with different positions in the optical cavity) are firstly prepared into a timed state by an external single photon field. During the excitation, the atoms grasp different phases which depend on the spatial positions of the atoms in the cavity. Due to strong resonant interaction between two atoms and optical cavity mode the absorbed input photon can be efficiently transferred from the atoms to the resonant cavity mode. We show that the quantum transfer is highly sensitive to the external excitation phases of atoms and it leads to quantum interference effects on the cavity mode excitation. Besides, the quantum transfer is also influenced by the dipole-dipole interaction dependent to the atomic distance. In this system the atomic positions also determine the coupling constants between atoms and cavity mode which causes additional interference effects to the photon exchange between atoms and cavity. Based on the characteristics of excitation phase we find that it is a feasible scheme to generate long-lived dark state and it could be useful for storage and manipulation of single photon fields by controlling the excitation phase.
Two-Photon Gateway in One-Atom Cavity Quantum Electrodynamics
Physical Review Letters, 2008
Single atoms absorb and emit light from a resonant laser beam photon by photon. We show that a single atom strongly coupled to an optical cavity can absorb and emit resonant photons in pairs. The effect is observed in a photon correlation experiment on the light transmitted through the cavity. We find that the atom-cavity system transforms a random stream of input photons into a correlated stream of output photons, thereby acting as a two-photon gateway. The phenomenon has its origin in the quantum anharmonicity of the energy structure of the atom-cavity system. Future applications could include the controlled interaction of two photons by means of one atom.
Generating two-photon entangled states in a driven two-atom system
Physical Review A, 2011
We describe a mechanism for a controlled generation of a pure Bell state with correlated atoms that involve two or zero excitations. The mechanism inhibits transitions into singly excited collective states of a two-atom system by shifting them from their unperturbed energies. The shift is accomplished by the dipole-dipole interaction between the atoms. The creation of the Bell state is found to be dependent on the relaxation of the atomic excitation. When the relaxation is not present or can be ignored, the state of the system evolves harmonically between a separable to the maximally entangled state. We follow the temporal evolution of the state and find that the concurrence can be different from zero only in the presence of the dipole-dipole interaction. Furthermore, in the limit of a large dipole-dipole interaction, the concurrence reduces to that predicted for an X state of the system. A general inequality is found which shows that the concurrence of an X-state system is a lower bound for the concurrence of the two-atom system. With the relaxation present, the general state of the system is a mixed state that under a strong dipole-dipole interaction reduces the system to an X-state form. We find that mixed states admit of lower level of entanglement, and the entanglement may occur over a finite range of time. A simple analytical expression is obtained for the steady-state concurrence which shows that there is a threshold value for the dipole-dipole interaction relative to the Rabi frequency of the driving field above which the atoms can be entangled over the entire time of the evolution.
Effective dynamics for two-atom entanglement and quantum information processing by coupled cavity QED systems
The European Physical Journal D, 2011
We propose a scheme for deterministic generation of entanglement embodied by two Λ-type atoms distributed in two coupled cavities. We study such a system in the dispersive atom-field interactions, where the dynamics of the system operates through the virtual population of both the atomic excited states and the photonic states in the cavities (plus the fiber). We verify the validity of the dynamics, and moreover, study the influences of the decoherence due to the spontaneous emission and photon leakage. We also apply the dynamics for realizing quantum state transfer and quantum phase gates.
Atom–Atom Entanglement in a Nonresonant Two-Photon Tavis–Cummings Model
2020
Entanglement between two identical two-level atoms (qubits) that interact nonresonantly with the thermal field of a single-mode ideal resonator via effective degenerate two-photon transitions is studied. Based on an exact solution for the time-dependent density matrix, negativity is calculated as a measure of atom entanglement. The effect detuning between the atomic frequencies and the doubled frequency of the resonator field has on the dynamics of qubit entanglement in cases of separable and entangled initial atomic states is investigated.
Resonant scheme for realizing quantum phase gates for two separate atoms via coupled cavities
Optics Communications, 2010
We propose a scheme for realizing conditional quantum phase gates for two atoms that are distributed in two coupled cavities. Due to the resonant interaction in temporal evolution of the entire system, the gate operation time is greatly reduced as compared with that of the nonresonant schemes. We study the influence of imperfections in the interaction and the effect of decoherence and find the gate to be robust. We discuss the issue related to the practical implementation and show that the gate is accessible within the current cavity QED technology.
Related papers
Two-photon exchange between two three-level atoms in separate cavities
Physical Review A, 2011
The temporal evolution of two coupled cavities, each containing a single three-level atom, is studied when the cavities exchange two coherent photons. The general state of the system is a linear superposition of symmetric and antisymmetric states with the symmetric states controlled by two of the four eigenfrequencies and the antisymmetric states by the other two. The system undergoes Rabi oscillations between the two symmetric (antisymmetric) states. There is state transfer between the cavities when both atoms are in the ground state and two photons are exchanged. In addition, there is also Rabi "flopping" whereby one atom is in the excited state and the other in the ground state and the roles are reversed in a periodic fashion by the exchange of two photons. The generation of entanglement can be explicitly given as a function of time. Models of coupled cavities are of interest in distributed quantum information and computation.
How to trap photons? Storing single-photon quantum states in collective atomic excitations
Optics Communications, 2000
We s h o w that it is possible to \store" quantum states of single-photon elds by mapping them onto collective meta-stable states of an optically dense, coherently driven medium inside an optical resonator. An adiabatic technique is suggested which a l l o ws to transfer non-classical correlations from traveling-wave single-photon wave-packets into atomic states and vise versa with nearly 100% e ciency. I n c o n trast to previous approaches involving single atoms, the present t e c hnique does not require the strong coupling regime corresponding to high-Q micro-cavities. Instead, intracavity Electromagnetically Induced Transparency is used to achieve a strong coupling between the cavity mode and the atoms.
Analyzing quantum jumps of one and two atoms strongly coupled to an optical cavity
Journal of The Optical Society of America, 2010
We induce quantum jumps between the hyperfine ground states of one and two Cesium atoms, strongly coupled to the mode of a high-finesse optical resonator, and analyze the resulting random telegraph signals. We identify experimental parameters to deduce the atomic spin state nondestructively from the stream of photons transmitted through the cavity, achieving a compromise between a good signal-to-noise ratio
Collective excitations of atoms and field modes in coupled cavities
Physica Scripta, 2014
The exact solution of the system consisted from two or three q-bits doped in coupled cavities is discussed. The problem of indistinguishable between the excited radiators and photons is analyzed using the intrinsic symmetry of the system. It is demonstrated that the solution is drastically simplified when the radiators and photons are considered as a new polariton excitations. The exact solution of Schrodinger equation is obtained for single and two excitations in each cavity taking into consideration the indistinguishable principle. This approach opens new possibilities in the interpretation of quantum entangled states in comparison with the traditional distinctive situation (see for example ) due to the decreasing of the number of degrees of freedoms in the system. Considering that the energies of coupling between the radiators and photons is larger than the coupling with external vacuum field, we have found the master equation for the dumping of collective excitations of the system of coupled radiators through the cavity fields. The time-dependence of population for new dressed quasi-levels of energy is obtained solving analytically and numerically the master equation.
Atoms versus photons as carriers of quantum states
Physical Review A, 2013
The problem of the complete transfer of quantum states and entanglement in a four-qubit system composed of two single-mode cavities and two two-level atoms is investigated. The transfer of single and double excitation states is discussed for two different coupling configurations between the qubits. In the first, the coupling is mediated by the atoms that simultaneously couple to the cavity modes. In the second configuration, each atom resides inside one of the cavities and the coupling between the cavities is mediated by the overlapping field modes. A proper choice of basis states makes it possible to identify states that could be completely transferred between themselves. Simple expressions are derived for the conditions for the complete transfer of quantum states and entanglement. These conditions impose severe constraints on the evolution of the system in the form of constants of motion. The constrains on the evolution of the system imply that not all states can evolve in time, and we find that the evolution of the entire system can be confined into that occurring among two states only. Detailed analysis show that in the case where the interaction is mediated by the atoms, only symmetric superposition states can be completely and reversibly transferred between the atoms and the cavity modes. In the case where the interaction is mediated by the overlapping field modes, both symmetric and antisymmetric superposition states can be completely transferred. We also show that the system is capable of generating purely photonic NOON states, but only if the coupling is mediated by the atoms, and demonstrate that the ability to generate the NOON states relies on perfect transfer of an entanglement from the atoms to the cavity modes.
Observation of oscillatory energy exchange in a coupled-atom-cavity system
Journal of The Optical Society of America, 1995
Observations of the oscillatory exchange of excitation between N two-state atoms and a single mode of a highfinesse optical cavity are reported in a regime of weak-field excitation and of comparable atomic and cavity damping rates. The observed frequencies of oscillation, approximately given by g p N , where g is the singlephoton Rabi frequency, are in reasonable agreement with theoretical predictions.
Heralded single-photon absorption by a single atom
Nature Physics, 2011
The emission and absorption of single photons by single atomic particles is a fundamental limit of matter-light interaction, manifesting its quantum mechanical nature. At the same time, as a controlled process it is a key enabling tool for quantum technologies, such as quantum optical information technology [1, 2] and quantum metrology . Controlling both emission and absorption will allow implementing quantum networking scenarios , where photonic communication of quantum information is interfaced with its local processing in atoms. In studies of single-photon emission, recent progress includes control of the shape, bandwidth, frequency, and polarization of single-photon sources , and the demonstration of atom-photon entanglement . Controlled absorption of a single photon by a single atom is much less investigated; proposals exist but only very preliminary steps have been taken experimentally such as detecting the attenuation and phase shift of a weak laser beam by a single atom , and designing an optical system that covers a large fraction of the full solid angle . Here we report the interaction of single heralded photons with a single trapped atom. We find strong correlations of the detection of a heralding photon with a change in the quantum state of the atom marking absorption of the quantum-correlated heralded photon. In coupling a single absorber with a quantum light source, our experiment demonstrates previously unexplored matter-light interaction, while opening up new avenues towards photon-atom entanglement conversion in quantum technology.
Atom-Resonant Heralded Single Photons by Interaction-Free Measurement
Physical Review Letters, 2011
We demonstrate the generation of rubidium-resonant heralded single photons for quantum memories. Photon pairs are created by cavity-enhanced down-conversion and narrowed in bandwidth to 7 MHz with a novel atom-based filter operating by “interaction-free measurement” principles. At least 94% of the heralded photons are atom-resonant as demonstrated by a direct absorption measurement with rubidium vapor. A heralded autocorrelation measurement shows gc(2)(0)=0.040±0.012, i.e., suppression of multiphoton contributions by a factor of 25 relative to a coherent state. The generated heralded photons can readily be used in quantum memories and quantum networks.
Strongly correlated quantum dynamics of multimode light coupled to a two-level atom in a cavity
2010
We study a composite multimode light-two-level atom system in a cavity. We show that coupling of the two-level atom to multiple modes of the light destroys the Mott phase of the composite system thus making the system less useful platform for developing concepts in quantum information processing.
Continuous Generation of Quantum Light from a Single Ground-State Atom in an Optical Cavity
Physical Review Letters, 2020
We show an optical wave-mixing scheme that generates quantum light by means of a single three-level atom. The atom couples to an optical cavity and two laser fields that together drive a cycling current within the atom. Weak driving in combination with strong atom-cavity coupling induces transitions in a harmonic ladder of dark states, accompanied by single-photon emission via a quantum Zeno effect and suppression of atomic excitation via quantum interference. For strong driving, the system can generate coherent or Schrödinger cat-like fields with frequencies distinct from those of the applied lasers.
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.