Atomtronics deals with matter-wave circuits of ultracold atoms manipulated through magnetic or laser-generated guides with different shapes and intensities. In this way, new types of quantum networks can be constructed in which coherent fluids are controlled with the know-how developed in the atomic and molecular physics community. In particular, quantum devices with enhanced precision, control, and flexibility of their operating conditions can be accessed. Concomitantly, new quantum simulators and emulators harnessing on the coherent current flows can also be developed. Here, the authors survey the landscape of atomtronics-enabled quantum technology and draw a roadmap for the field in the near future. The authors review some of the latest progress achieved in matter-wave circuits{\textquoteright} design and atom-chips. Atomtronic networks are deployed as promising platforms for probing many-body physics with a new angle and a new twist. The latter can be done at the level of both equilibrium and nonequilibrium situations. Numerous relevant problems in mesoscopic physics, such as persistent currents and quantum transport in circuits of fermionic or bosonic atoms, are studied through a new lens. The authors summarize some of the atomtronics quantum devices and sensors. Finally, the authors discuss alkali-earth and Rydberg atoms as potential platforms for the realization of atomtronic circuits with special features.

}, doi = {10.1116/5.0026178}, url = {https://doi.org/10.1116/5.0026178}, author = {L. Amico and M. Boshier and G. Birkl and A. Minguzzi and C. Miniatura and L.-C. Kwek and D. Aghamalyan and V. Ahufinger and D. Anderson and N. Andrei and A. S. Arnold and M. Baker and T. A. Bell and T. Bland and J. P. Brantut and D. Cassettari and W. J. Chetcuti and F. Chevy and R. Citro and S. De Palo and R. Dumke and M. Edwards and R. Folman and J. Fortagh and S. A. Gardiner and B. M. Garraway and G. Gauthier and A. G{\"u}nther and T. Haug and C. Hufnagel and M. Keil and P. Ireland and M. Lebrat and W. Li and L. Longchambon and J. Mompart and O. Morsch and P. Naldesi and T. W. Neely and M. Olshanii and E. Orignac and S. Pandey and A. P{\'e}rez-Obiol and H. Perrin and L. Piroli and J. Polo and A. L. Pritchard and N. P. Proukakis and C. Rylands and H. Rubinsztein-Dunlop and F. Scazza and S. Stringari and F. Tosto and A. Trombettoni and N. Victorin and W. von Klitzing and D. Wilkowski and K. Xhani and A. Yakimenko} } @article {339, title = {Artificial gauge field switching using orbital angular momentum modes in optical waveguides}, journal = {Light: Science \& Applications}, volume = {9}, year = {2020}, month = {2020/08/28}, pages = {150}, abstract = {The discovery of artificial gauge fields controlling the dynamics of uncharged particles that otherwise elude the influence of standard electromagnetic fields has revolutionised the field of quantum simulation. Hence, developing new techniques to induce these fields is essential to boost quantum simulation of photonic structures. Here, we experimentally demonstrate the generation of an artificial gauge field in a photonic lattice by modifying the topological charge of a light beam, overcoming the need to modify the geometry along the evolution or impose external fields. In particular, we show that an effective magnetic flux naturally appears when a light beam carrying orbital angular momentum is injected into a waveguide lattice with a diamond chain configuration. To demonstrate the existence of this flux, we measure an effect that derives solely from the presence of a magnetic flux, the Aharonov-Bohm caging effect, which is a localisation phenomenon of wavepackets due to destructive interference. Therefore, we prove the possibility of switching on and off artificial gauge fields just by changing the topological charge of the input state, paving the way to accessing different topological regimes in a single structure, which represents an important step forward for optical quantum simulation.

}, isbn = {2047-7538}, doi = {https://doi.org/10.1038/s41377-020-00385-6}, url = {https://www.nature.com/articles/s41377-020-00385-6}, author = {C. J{\"o}rg and G. Queralt{\'o} and M. Kremer and G. Pelegr{\'\i} and J. Schulz and A. Szameit and G. von Freymann and J. Mompart and V. Ahufinger} } @article {319, title = {Knotting fractional-order knots with the polarization state of light}, journal = {Nature Photonics }, volume = {13}, year = {2019}, chapter = {569}, abstract = {The fundamental polarization singularities of monochromatic light are normally associated with invariance under coordinated rotations: symmetry operations that rotate the spatial dependence of an electromagnetic field by an angle\ *θ*\ and its polarization by a multiple\ *γθ*\ of that angle. These symmetries are generated by mixed angular momenta of the form\ *J*_{γ} = *L* + *γS*, and they generally induce M{\"o}bius-strip topologies, with the coordination parameter\ *γ*\ restricted to integer and half-integer values. In this work we construct beams of light that are invariant under coordinated rotations for arbitrary rational\ *γ*, by exploiting the higher internal symmetry of {\textquoteleft}bicircular{\textquoteright} superpositions of counter-rotating circularly polarized beams at different frequencies. We show that these beams have the topology of a torus knot, which reflects the subgroup generated by the torus-knot angular momentum\ *J*_{γ}, and we characterize the resulting optical polarization singularity using third- and higher-order field moment tensors, which we experimentally observe using nonlinear polarization tomography.

STIRAP (stimulated Raman adiabatic passage) is a powerful laser-based method, usually involving two photons, for efficient and selective transfer of populations between quantum states. A particularly interesting feature is the fact that the coupling between the initial and the final quantum states is via an intermediate state, even though the lifetime of the latter can be much shorter than the interaction time with the laser radiation. Nevertheless, spontaneous emission from the intermediate state is prevented by quantum interference. Maintaining the coherence between the initial and final state throughout the transfer process is crucial. STIRAP was initially developed with applications in chemical dynamics in mind. That is why the original paper of 1990 was published in The Journal of Chemical Physics. However, from about the year 2000, the unique capabilities of STIRAP and its robustness with respect to small variations in some experimental parameters stimulated many researchers to apply the scheme to a variety of other fields of physics. The successes of these efforts are documented in this collection of articles. In Part A the experimental success of STIRAP in manipulating or controlling molecules, photons, ions or even quantum systems in a solid-state environment is documented. After a brief introduction to the basic physics of STIRAP, the central role of the method in the formation of ultracold molecules is discussed, followed by a presentation of how precision experiments (measurement of the upper limit of the electric dipole moment of the electron or detecting the consequences of parity violation in chiral molecules) or chemical dynamics studies at ultralow temperatures benefit from STIRAP. Next comes the STIRAP-based control of photons in cavities followed by a group of three contributions which highlight the potential of the STIRAP concept in classical physics by presenting data on the transfer of waves (photonic, magnonic and phononic) between respective waveguides. The works on ions or ion strings discuss options for applications, e.g. in quantum information. Finally, the success of STIRAP in the controlled manipulation of quantum states in solid-state systems, which are usually hostile towards coherent processes, is presented, dealing with data storage in rare-earth ion doped crystals and in nitrogen vacancy (NV) centers or even in superconducting quantum circuits. The works on ions and those involving solid-state systems emphasize the relevance of the results for quantum information protocols. Part B deals with theoretical work, including further concepts relevant to quantum information or invoking STIRAP for the manipulation of matter waves. The subsequent articles discuss the experiments underway to demonstrate the potential of STIRAP for populating otherwise inaccessible high-lying Rydberg states of molecules, or controlling and cooling the translational motion of particles in a molecular beam or the polarization of angular-momentum states. The series of articles concludes with a more speculative application of STIRAP in nuclear physics, which, if suitable radiation fields become available, could lead to spectacular results.

}, doi = {10.1088/1361-6455/ab3995}, url = {https://doi.org/10.1088\%2F1361-6455\%2Fab3995}, author = {K. Bergmann and H. C. N{\"a}gerl and C. Panda and G. Gabrielse and E. Miloglyadov and M. Quack and G. Seyfang and G. Wichmann and S. Ospelkaus and A. Kuhn and S. Longhi and A. Szameit and P. Pirro and B. Hillebrands and X.-F. Zhu and J. Zhu and M. Drewsen and W. K. Hensinger and S. Weidt and T. Halfmann and H.-L. Wang and G. Sorin Paraoanu and N. V. Vitanov and J. Mompart and T. Busch and T. J. Barnum and D. D. Grimes and R. W. Field and M. G. Raizen and E. Narevicius and M. Auzinsh and D. Budker and A. P{\'a}lffy and C. H. Keitel} } @article {280, title = {Atomic-frequency-comb quantum memory via piecewise adiabatic passage}, journal = {Phys. Rev. A}, volume = {98}, year = {2018}, month = {Oct}, pages = {043834}, abstract = {In this paper, we propose a method to create an atomic frequency comb (AFC) in hot atomic vapors using the piecewise adiabatic passage (PAP) technique. Due to the Doppler effect, the trains of pulses used for PAP give rise to a velocity-dependent transfer of the atomic population from the initial state to the target one, thus forming a velocity comb whose periodicity depends not only on the repetition rate of the applied pulses but also on the specific atomic transitions considered. We highlight the advantages of using this transfer technique with respect to standard methods and discuss, in particular, its application to store a single telecom photon in an AFC quantum memory using a high density Ba atomic vapor.

}, doi = {10.1103/PhysRevA.98.043834}, url = {https://link.aps.org/doi/10.1103/PhysRevA.98.043834}, author = {J. L. Rubio and D. Viscor and J. Mompart and V. Ahufinger} } @article {Turpin:15, title = {Transformation of vector beams with radial and azimuthal polarizations in biaxial crystals}, journal = {J. Opt. Soc. Am. A}, volume = {32}, number = {5}, year = {2015}, month = {May}, pages = {1012{\textendash}1016}, publisher = {OSA}, abstract = {We present both experimentally and theoretically the transformation of radially and azimuthally polarized vector beams when they propagate through a biaxial crystal and are transformed by the conical refraction phenomenon. We show that, at the focal plane, the transverse pattern is formed by a ring-like light structure with an azimuthal node, this node being found at diametrically opposite points of the ring for radial/azimuthal polarizations. We also prove that the state of polarization of the transformed beams is conical refraction-like, i.e., that every two diametrically opposite points of the light ring are linearly orthogonally polarized.

}, keywords = {Birefringence, Crystal optics, Polarization}, doi = {10.1364/JOSAA.32.001012}, url = {http://josaa.osa.org/abstract.cfm?URI=josaa-32-5-1012}, author = {A. Turpin and A. Vargas and A. Lizana and F. A. Torres-Ruiz and I. Est{\'e}vez and I. Moreno and J. Campos and J. Mompart} } @article {134, title = {Light spectral filtering based on spatial adiabatic passage}, journal = {Light: Science \& Applications}, volume = {2}, year = {2013}, month = {08/2013}, chapter = {e90}, abstract = {We present the first experimental realization of a light spectral filter based on the spatial adiabatic passage technique. We demonstrate that a fully integrable CMOS-compatible system of three coupled identical total internal reflection silicon oxide waveguides with variable separation along their propagation direction can be used simultaneously as a low- and high-pass spectral filter within the visible range of wavelengths. Light is injected into the right waveguide, and after propagating along the system, long wavelengths are transferred into the left output, whereas short wavelengths propagate to the right and central outputs. The stopband reaches values up to 11 dB for the left output and approximately 20 dB for the right plus central outputs. The passband values are close to 0 dB for both cases. We also demonstrate that the filtering characteristics of the device can be controlled by modifying the parameter values, which define the geometry of the triple-waveguide system. However, the general filtering behavior of the system does not critically depend on technological variations. Thus, the spatial adiabatic passage filtering approach constitutes an alternative to other integrated filtering devices, such as interference or absorbance-based filters.}, keywords = {CMOS-compatible technology, integrated optics devices, spatial adiabatic passage, wavelength filtering devices}, doi = {doi:10.1038/lsa.2013.46}, url = {http://www.nature.com/lsa/journal/v2/n8/full/lsa201346a.html}, author = {R. Menchon-Enrich and A. Llobera and J. Vila-Planas and V. J Cadarso and J. Mompart and V. Ahufinger} } @article {126, title = {Nanoscale resolution for fluorescence microscopy via adiabatic passage}, journal = {Optics Express}, volume = {21}, number = {19}, year = {2013}, chapter = {22139}, abstract = {We propose the use of the subwavelength localization via adiabatic passage technique for fluorescence microscopy with nanoscale resolution in the far field. This technique uses a Λ-type medium coherently coupled to two laser pulses: the pump, with a node in its spatial profile, and the Stokes. The population of the Λ system is adiabatically transferred from one ground state to the other except at the node position, yielding a narrow population peak. This coherent localization allows fluorescence imaging with nanometer lateral resolution. We derive an analytical expression to asses the resolution and perform a comparison with the coherent population trapping and the stimulated-emission-depletion techniques.}, keywords = {Atomic and molecular physics, Microscopy, Quantum optics}, issn = {1094-4087}, doi = {10.1364/OE.21.022139}, url = {http://dx.doi.org/10.1364/OE.21.022139}, author = {J. L. Rubio and D. Viscor and V. Ahufinger and J. Mompart} } @article {PhysRevA.86.063409, title = {Single-site addressing of ultracold atoms beyond the diffraction limit via position-dependent adiabatic passage}, journal = {Phys. Rev. A}, volume = {86}, year = {2012}, month = {12/2012}, pages = {063409}, publisher = {American Physical Society}, abstract = {We propose a single-site addressing implementation based on the subwavelength localization via adiabatic passage (SLAP) technique. We consider a sample of ultracold neutral atoms loaded into a two-dimensional optical lattice with one atom per site. Each atom is modeled by a three-level Λ system in interaction with a pump and a Stokes laser pulse. Using a pump field with a node in its spatial profile, the atoms at all sites are transferred from one ground state of the system to the other via stimulated Raman adiabatic passage, except the one at the position of the node that remains in the initial ground state. This technique allows for the preparation, manipulation, and detection of atoms with a spatial resolution better than the diffraction limit, which either relaxes the requirements on the optical setup used or extends the achievable spatial resolution to lattice spacings smaller than accessible to date. In comparison to techniques based on coherent population trapping, SLAP gives a higher addressing resolution and has additional advantages such as robustness against parameter variations, coherence of the transfer process, and the absence of photon induced recoil. Additionally, the advantages of our proposal with respect to adiabatic spin-flip techniques are highlighted. Analytic expressions for the achievable addressing resolution and efficiency are derived and compared to numerical simulations for 87Rb atoms in state-of-the-art optical lattices.}, doi = {10.1103/PhysRevA.86.063409}, url = {http://link.aps.org/doi/10.1103/PhysRevA.86.063409}, author = {D. Viscor and J. L. Rubio and G. Birkl and J. Mompart and V. Ahufinger} } @article {PhysRevA.86.053827, title = {Two-color quantum memory in double-Λ media}, journal = {Phys. Rev. A}, volume = {86}, year = {2012}, month = {11/2012}, pages = {053827}, publisher = {American Physical Society}, abstract = {We propose a quantum memory for a single-photon wave packet in a superposition of two different colors, i.e., two different frequency components, using the electromagnetically induced transparency technique in a double-Λ system. We examine a specific configuration in which the two frequency components are able to exchange energy through a four-wave mixing process as they propagate, so the state of the incident photon is recovered periodically at certain positions in the medium. We investigate the propagation dynamics as a function of the relative phase between the coupling beams and the input single-photon frequency components. Moreover, by considering time-dependent coupling beams, we numerically simulate the storage and retrieval of a two-frequency-component single-photon qubit.}, doi = {10.1103/PhysRevA.86.053827}, url = {http://link.aps.org/doi/10.1103/PhysRevA.86.053827}, author = {D. Viscor and V. Ahufinger and J. Mompart and A. Zavatta and G. C. La Rocca and M. Artoni} } @article {0953-4075-44-19-195504, title = {Optical quantum memory for polarization qubits with V -type three-level atoms}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, volume = {44}, number = {19}, year = {2011}, pages = {195504}, abstract = {We investigate an optical quantum memory scheme with V -type three-level atoms based on the controlled reversible inhomogeneous broadening technique. We theoretically show the possibility of storing and retrieving a weak light pulse interacting with the two optical transitions of the system. This scheme implements a quantum memory for a polarization qubit{\textemdash}a single photon in an arbitrary polarization state{\textemdash}without the need of two spatially separated two-level media, thus offering the advantage of experimental compactness overcoming the limitations due to mismatching and unequal efficiencies that can arise in spatially separated memories. The effects of a relative phase change between the atomic levels, as well as of phase noise due to, for example, the presence of spurious electric and magnetic fields are analysed.}, url = {http://stacks.iop.org/0953-4075/44/i=19/a=195504}, author = {D. Viscor and A. Ferraro and Yu. V. Loiko and R. Corbal{\'a}n and J. Mompart and V. Ahufinger} } @article {PhysRevA.84.042314, title = {Quantum-state storage and processing for polarization qubits in an inhomogeneously broadened Λ-type three-level medium}, journal = {Phys. Rev. A}, volume = {84}, year = {2011}, month = {Oct}, pages = {042314}, publisher = {American Physical Society}, abstract = {We address the propagation of a single-photon pulse with two polarization components, i.e., a polarization qubit, in an inhomogeneously broadened {\textquotedblleft}phaseonium{\textquotedblright} Λ-type three-level medium. We combine some of the nontrivial propagation effects characteristic for this kind of coherently prepared systems and the controlled reversible inhomogeneous broadening technique to propose several quantum information-processing applications, such as a protocol for polarization qubit filtering and sieving as well as a tunable polarization beam splitter. Moreover, we show that by imposing a spatial variation of the atomic coherence phase, an efficient quantum memory for the incident polarization qubit can be also implemented in Λ-type three-level systems.}, doi = {10.1103/PhysRevA.84.042314}, url = {http://link.aps.org/doi/10.1103/PhysRevA.84.042314}, author = {D. Viscor and A. Ferraro and Yu. V. Loiko and J. Mompart and V. Ahufinger} } @article {PhysRevA.81.033420, title = {Dipole spectrum structure of nonresonant nonpertubative driven two-level atoms}, journal = {Phys. Rev. A}, volume = {81}, year = {2010}, month = {Mar}, pages = {033420}, publisher = {American Physical Society}, abstract = {We analyze the dipole spectrum of a two-level atom excited by a nonresonant intense monochromatic field under the electric dipole approximation and beyond the rotating wave approximation. We show that the apparently complex spectral structure can be completely described by two families: harmonic frequencies of the driving field and field-induced nonlinear fluorescence. Our formulation of the problem provides quantitative laws for the most relevant spectral features: harmonic ratios and phases, nonperturbative Stark shift, and frequency limits of the harmonic plateau. In particular, we demonstrate the locking of the harmonic phases at the wings of the plateau opening the possibility of ultrashort pulse generation through harmonic filtering.}, doi = {10.1103/PhysRevA.81.033420}, url = {http://link.aps.org/doi/10.1103/PhysRevA.81.033420}, author = {A. Pic{\'o}n and L. Roso and J. Mompart and O. Varela and V. Ahufinger and R. Corbal{\'a}n and L. Plaja} } @article {PhysRevA.79.053809, title = {Doppler-free adiabatic self-induced transparency}, journal = {Phys. Rev. A}, volume = {79}, year = {2009}, month = {May}, pages = {053809}, publisher = {American Physical Society}, abstract = {We demonstrate that a Doppler-broadened two-level medium can be made transparent to a laser pulse by an appropriate adiabatic variation in the laser field amplitude and its nominal detuning. This technique of adiabatic self-induced transparency (ASIT) is compared with the well-known self-induced transparency phenomenon, showing that the adiabatic method is much more robust against variations in the system parameters. We also discuss a possible experimental implementation of ASIT using R87b atoms.}, doi = {10.1103/PhysRevA.79.053809}, url = {http://link.aps.org/doi/10.1103/PhysRevA.79.053809}, author = {Yu. V. Loiko and C. Serrat and R. Vilaseca and V. Ahufinger and J. Mompart and R. Corbal{\'a}n} } @article {PhysRevA.75.023801, title = {Ultrashort pulse control of space-dependent excitations in a three-level system}, journal = {Phys. Rev. A}, volume = {75}, year = {2007}, month = {Feb}, pages = {023801}, publisher = {American Physical Society}, abstract = {Coherent control of regions with spatial excitation of populations and coherence between two lower states in three-level Λ-type quantum systems mediated by the self-induced transparency (SIT) phenomenon is theoretically investigated with one- and two-color ultrashort pulses and with pulse sequences beyond the slowly varying envelope (SVEA) and rotating wave (RWA) approximations. The effects of different parameters characterizing the pulses and the medium on the location as well as the width of such excited regions have been studied numerically by means of the finite-difference time-domain (FDTD) method. It has been determined that with a scheme of two-pulse excitation one can effectively control the position at which the region is written and its width. In particular, the position of the excited region can be controlled by the area of the pulses. We find that the maximum value of the population transferred to the lower excited state depends on the detuning of the pulses with respect to the one-photon resonances, and that both position and width of the region also depend on the temporal duration of the pulses. We show how after the excited region is written, its position can be shifted by additional pulses. On the basis of numerical results, scaling laws are formulated for the reported phenomena. With such control, the width of the region excited inside the medium can be reduced to the order of the wavelength of the light.}, doi = {10.1103/PhysRevA.75.023801}, url = {http://link.aps.org/doi/10.1103/PhysRevA.75.023801}, author = {Yu. V. Loiko and C. Serrat and R. Vilaseca and V. Ahufinger and J. Mompart and R. Corbal{\'a}n} } @article {PhysRevLett.91.083901, title = {Cavity Solitons in Two-Level Lasers with Dense Amplifying Medium}, journal = {Phys. Rev. Lett.}, volume = {91}, year = {2003}, month = {Aug}, pages = {083901}, publisher = {American Physical Society}, abstract = {Local-field effects are known to induce bistability in dense optical media. We examine theoretically whether this property is preserved in broad-area cavities, and show that bistability between the homogeneous lasing and nonlasing states of the system persists provided a Fourier filtering technique is used to prevent off-axis emission. The resulting bistability gives rise to spatial light localization in the form of cavity solitons, which exhibit a particularly large degree of plasticity as a function of the characteristics of the addressing beam. This is the simplest laser able to sustain cavity solitons.}, doi = {10.1103/PhysRevLett.91.083901}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.91.083901}, author = {V. Ahufinger and J. Garc{\'\i}a-Ojalvo and J. Mompart and M. C. Torrent and R. Corbal{\'a}n and R. Vilaseca} } @article {1464-4266-5-3-301, title = {Enlargement of the inversionless lasing domain by using broad-area cavities}, journal = {Journal of Optics B: Quantum and Semiclassical Optics}, volume = {5}, number = {3}, year = {2003}, pages = {201}, abstract = {We investigate analytically and numerically the role of diffraction in the operation of a broad-area inversionless laser in a cascade three-level configuration. Through a linear stability analysis of the trivial non-lasing solution and numerical integration of the corresponding Maxwell{\textendash}Schr{\"o}dinger equations, we show that off-axis emission allows stationary inversionless lasing over a cavity detuning range much larger than in small-aspect-ratio cavities and in conventionally inverted three-level lasers. In addition, we investigate inversionless lasing in a self-pulsing regime in the presence of diffraction, which leads to rich spatiotemporal dynamics.}, url = {http://stacks.iop.org/1464-4266/5/i=3/a=301}, author = {J. Mompart and M. C. Torrent and V. Ahufinger and J. Garc{\'\i}a-Ojalvo and R. Corbal{\'a}n and R. Vilaseca} } @article {PhysRevA.59.3038, title = {Giant pulse lasing in three-level systems}, journal = {Phys. Rev. A}, volume = {59}, year = {1999}, month = {Apr}, pages = {3038{\textendash}3043}, publisher = {American Physical Society}, abstract = {We propose an alternative method to Q switching for generating giant pulses of laser light in three-level media. This mehod is based on the presence of an external coherent field driving one transition to allow the accumulation of a large population inversion in the other transition without laser oscillation even in a cavity with high-Q factor. The switching off of the external coherent field causes the development of the giant pulse. Different time profiles for the switching off of the external field have been investigated.}, doi = {10.1103/PhysRevA.59.3038}, url = {http://link.aps.org/doi/10.1103/PhysRevA.59.3038}, author = {J. Mompart and R. Corbal{\'a}n and R. Vilaseca} } @article { ISI:000082230000012, title = {Quantum interference and quantum-Zeno effect in amplification without inversion}, journal = {Laser Physics}, volume = {9}, number = {9}, year = {1999}, month = {JUL-AUG}, pages = {844-857}, publisher = {{INTERPERIODICA}}, address = {{PO BOX 1831, BIRMINGHAM, AL 35201-1831 USA}}, abstract = {We analyze amplification without inversion (AWI) in different homogeneously broadened closed three-level systems in the framework of both density-matrix and quantum-jump formalisms. With the density-matrix formalism we study the nature of quantum interference in these systems; determine analytically the condition for AWI and locate the position of maxima and minima in the probe absorption spectrum. Within the quantum-jump formalism we calculate the relative probabilities of the various physical processes responsible for probe field amplification and absorption, and analyze the role of the quantum-Zeno effect in AWI. The result is that AWI in the h and p schemes is due to one-photon processes while for V and Lambda schemes are due to two-photon processes. We also show that AWI in V and h schemes always occurs in the quantum-Zeno regime, while this regime is not necessary for AWI in the Lambda and p schemes.}, issn = {1054-660X}, author = {J. Mompart and V. Ahufinger and F. Silva and R. Corbal{\'a}n and R. Vilaseca} } @article {Mompart1998299, title = {Lasing without inversion in the V-type three-level system under the two-photon resonance condition}, journal = {Optics Communications}, volume = {147}, number = {4{\textendash}6}, year = {1998}, pages = {299 - 304}, abstract = {We investigate lasing without inversion in the closed V-type three-level system with off-resonant driving and laser fields by using both density-matrix and quantum-jump approaches. We demonstrate analytically and numerically that, under the two-photon resonance condition, it is possible to relax the severe conditions between spontaneous population decay and incoherent pump rates needed in the resonant case. We extend the same analysis to the remaining three-level systems.}, keywords = {atomic coherence}, issn = {0030-4018}, doi = {http://dx.doi.org/10.1016/S0030-4018(97)00490-2}, url = {http://www.sciencedirect.com/science/article/pii/S0030401897004902}, author = {J. Mompart and R. Corbal{\'a}n and R. Vilaseca} } @article {1355-5111-10-2-005, title = {Self-pulsing lasing without inversion in the double-Λ scheme}, journal = {Quantum and Semiclassical Optics: Journal of the European Optical Society Part B}, volume = {10}, number = {2}, year = {1998}, pages = {309}, abstract = {Lasing without inversion (LWI) is investigated from a nonlinear dynamics point of view for an atomic system with three coupled J = 0-1 transitions. The driving and generated fields couple two of these transitions defining a double- $\#$$\#$IMG$\#$$\#$ [http://ej.iop.org/images/1355-5111/10/2/005/img7.gif] scheme. In addition, two incoherent pump fields are acting on the system. We find that LWI can occur not only in a continuous wave regime but also in a self-pulsing regime. A clear physical interpretation of the origin of this self-pulsing LWI is given. We obtain analytically the threshold driving field intensity needed to achieve both continuous wave and self-pulsing LWI emission. For large enough cavity losses, the system can reach either continuous wave or self-pulsing regimes by only changing the driving field intensity.}, url = {http://stacks.iop.org/1355-5111/10/i=2/a=005}, author = {R. Corbal{\'a}n and J. Mompart and R. Vilaseca and E Arimondo} } @article {1355-5111-10-4-009, title = {Self-pulsing lasing without inversion in the double-Λ scheme}, journal = {Quantum and Semiclassical Optics: Journal of the European Optical Society Part B}, volume = {10}, number = {4}, year = {1998}, pages = {661}, abstract = {In this recently published article the address of the fourth author of this article was incorrectly stated. The correction affiliation for Professor Arimondo should read; Dipartimento di Fisica and Istituto Nazionale di Fisica della Materia, Unit{\'a} di Pisa, Universit{\'a} di Pisa, I-56100 Pisa, Italy.}, url = {http://stacks.iop.org/1355-5111/10/i=4/a=009}, author = {R. Corbal{\'a}n and J. Mompart and R. Vilaseca and E Arimondo} }