Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1504.07123 · Journal of Experimental and Theoretical Physics

Nonclassical properties and quantum resources of hierarchical photonic superposition states

Tyler J. Volkoff

Published Nov 1, 2015• 10 citations
arXivHTMLPDF

Abstract

We motivate and introduce a class of “hierarchical” quantum superposition states of N coupled quantum oscillators. Unlike other well-known multimode photonic Schrödinger-cat states such as entangled coherent states, the hierarchical superposition states are characterized as two-branch superpositions of tensor products of single-mode Schrödinger-cat states. In addition to analyzing the photon statistics and quasiprobability distributions of prominent examples of these nonclassical states, we consider their usefulness for highprecision quantum metrology of nonlinear optical Hamiltonians and quantify their mode entanglement. We propose two methods for generating hierarchical superpositions in N = 2 coupled microwave cavities, exploiting currently existing quantum optical technology for generating entanglement between spatially separated electromagnetic field modes.

DOI
10.1134/s1063776115110187

Related papers

Nonclassical properties and generation of quantum superpositions of two coherent states

Anna Napoli, ANTONINO MESSINA

Nonclassical properties of a particular class of quantum superpositions of two coherent states of a single-mode quantized electromagnetic field are brought to light and discussed. A new and simple way of engineering such states is presented. Our proposal, developed in the context of micromaser theory, exploits the passage of one atom only through a high- Q bimodal cavity supporting two electromagnetic modes of different frequencies.

Journal of Optics B Quantum and Semiclassical Optics•May 24, 2000•2 citations

Two-mode squeezed states as Schrödinger cat-like states

Enky Oudot, Pavel Sekatski, Florian Fröwis +2 more

In recent years, there has been an increased interest in the generation of superposition of coherent states with opposite phases, the so-called photonic Schrodinger-cat states. These experiments are very challenging and so far, cats involving small photon numbers only have been implemented. Here, we propose to consider two-mode squeezed states as examples of a Schrodinger-cat-like state. In particular, we are interested in several criteria aiming to identify quantum states that are macroscopic superpositions in a more general sense. We show how these criteria can be extended to continuous variable entangled states. We apply them to various squeezed states, argue that two-mode squeezed vacuum states belong to a class of general Schrodinger-cat states and compare the size of states obtained in several experiments. Our results not only promote two-mode squeezed states for exploring quantum effects at the macroscopic level but also provide direct measures to evaluate their usefulness for quantum metrology.

arXiv:1410.8421•Journal of the Optical Society of America B•Sep 24, 2015•30 citations

Nonclassical properties of correlated two-mode Schrödinger cat states

Christopher C. Gerry, R. Grobe

We generalize the concept of Schr\"odinger cat states to macroscopic superpositions of two pairs coherent states. We show that these states can have various nonclassical features such as the violation of the Cauchy-Schwarz inequality, sub-Poissonian photon-number statistics, and squeezing. We propose schemes to generate these states.

Physical Review A•Feb 1, 1995•64 citations

Two-mode photon added Schrödinger cat states: nonclassicality and entanglement

S. Nibedita Swain, Yashovardhan Jha, Prasanta Kumar Panigrahi

The concept of a photon added two-mode Schrödinger cat state in which both modes are independent is introduced, and their nonclassical properties and entanglement are studied. The introduced states emerge as eigenstates of f 1 f 2 a 1 a 2 , where f 1 , f 2 are nonlinear functions of the number operator, and a 1 , a 2 are annihilation operators. We study the evolution of these states under canonical transformation using the parity operator for the case of standard coherent states of the harmonic oscillator. The nonclassical properties of these states are evaluated especially by considering sub-Poissonian photon statistics and photon number distribution. Interestingly, the addition of photons leads to shifting the region in which photon number distribution shows oscillatory behavior. In addition, the entanglement of introduced states is quantitatively analyzed using concurrence. We observe that the state approaches maximum entanglement more rapidly after the addition of photons.

arXiv:2202.00518•Journal of the Optical Society of America B•Sep 27, 2022•5 citations

Entanglement of two-mode Schrödinger cats

D. B. Horoshko, Giuseppe Patera, Stephan De Bièvre +1 more

Quantum superpositions of coherent states are produced both in microwave and optical domains, and are considered realizations of the famous “Schroedinger cat” state. The recent progress shows an increase in the number of components and the number of modes involved. Our work gives a theoretical treatment of multicomponent two-mode Schroedinger cat states. We consider a class of single-mode states, which are superpositions of N coherent states lying on a circle in the phase space. In this class we consider an orthonormal basis created by rotationally-invariant circular states (RICS). A two-mode extension of this basis is created by splitting a single-mode RICS on a balanced beam-splitter. After performing a symmetric (Loewdin) orthogonalization of the sets of coherent states in both modes we obtain the Schmidt decomposition of the two-mode state, and therefore an analytic expression for its entanglement. We show that the states obtained by splitting a RICS are generalizations of Bell states of two qubits to the case of N -level systems encoded into superpositions of coherent states on the circle, and we propose for them the name of generalized quasi-Bell states. We show that an exact probabilistic teleportation of arbitrary superposition of coherent states on the circle is possible with such a state used as shared resource.

SPIE Quantum Technologies•May 21, 2018•1 citation

Nonclassical properties and entanglement of superposition of two-mode separable nonlinear coherent states

Davood Afshar, Azam Anbaraki

Quasi Bell states are introduced as a result of superposition of two-mode separable nonlinear coherent states. In this paper, we consider the nonlinearity function related to the harmonious states. To evaluate the effectiveness of these states in quantum information theory, nonclassical properties such as photon statistics, squeezing, and entanglement are studied. The entanglement of these states is examined by calculating the concurrence. According to our calculations, three of the introduced states are maximally entangled states. In addition, the cross-correlation function of the three maximally entangled states is less than 1 for all values of |α|2.

Journal of the Optical Society of America B•Mar 7, 2016•20 citations
We motivate and introduce a class of “hierarchical” quantum superposition states of N coupled quantum oscillators. Unlike other well-known multimode photonic Schrödinger-cat states such as entangled coherent states, the hierarchical superposition states are characterized as two-branch superpositions of tensor products of single-mode Schrödinger-cat states. In addition to analyzing the photon statistics and quasiprobability distributions of prominent examples of these nonclassical states, we consider their usefulness for highprecision quantum metrology of nonlinear optical Hamiltonians and quantify their mode entanglement. We propose two methods for generating hierarchical superpositions in N = 2 coupled microwave cavities, exploiting currently existing quantum optical technology for generating entanglement between spatially separated electromagnetic field modes.
In recent years, there has been an increased interest in the generation of superposition of coherent states with opposite phases, the so-called photonic Schrodinger-cat states. These experiments are very challenging and so far, cats involving small photon numbers only have been implemented. Here, we propose to consider two-mode squeezed states as examples of a Schrodinger-cat-like state. In particular, we are interested in several criteria aiming to identify quantum states that are macroscopic superpositions in a more general sense. We show how these criteria can be extended to continuous variable entangled states. We apply them to various squeezed states, argue that two-mode squeezed vacuum states belong to a class of general Schrodinger-cat states and compare the size of states obtained in several experiments. Our results not only promote two-mode squeezed states for exploring quantum effects at the macroscopic level but also provide direct measures to evaluate their usefulness for quantum metrology.
The concept of a photon added two-mode Schrödinger cat state in which both modes are independent is introduced, and their nonclassical properties and entanglement are studied. The introduced states emerge as eigenstates of f 1 f 2 a 1 a 2 , where f 1 , f 2 are nonlinear functions of the number operator, and a 1 , a 2 are annihilation operators. We study the evolution of these states under canonical transformation using the parity operator for the case of standard coherent states of the harmonic oscillator. The nonclassical properties of these states are evaluated especially by considering sub-Poissonian photon statistics and photon number distribution. Interestingly, the addition of photons leads to shifting the region in which photon number distribution shows oscillatory behavior. In addition, the entanglement of introduced states is quantitatively analyzed using concurrence. We observe that the state approaches maximum entanglement more rapidly after the addition of photons.
Quantum superpositions of coherent states are produced both in microwave and optical domains, and are considered realizations of the famous “Schroedinger cat” state. The recent progress shows an increase in the number of components and the number of modes involved. Our work gives a theoretical treatment of multicomponent two-mode Schroedinger cat states. We consider a class of single-mode states, which are superpositions of N coherent states lying on a circle in the phase space. In this class we consider an orthonormal basis created by rotationally-invariant circular states (RICS). A two-mode extension of this basis is created by splitting a single-mode RICS on a balanced beam-splitter. After performing a symmetric (Loewdin) orthogonalization of the sets of coherent states in both modes we obtain the Schmidt decomposition of the two-mode state, and therefore an analytic expression for its entanglement. We show that the states obtained by splitting a RICS are generalizations of Bell states of two qubits to the case of N -level systems encoded into superpositions of coherent states on the circle, and we propose for them the name of generalized quasi-Bell states. We show that an exact probabilistic teleportation of arbitrary superposition of coherent states on the circle is possible with such a state used as shared resource.
Quasi Bell states are introduced as a result of superposition of two-mode separable nonlinear coherent states. In this paper, we consider the nonlinearity function related to the harmonious states. To evaluate the effectiveness of these states in quantum information theory, nonclassical properties such as photon statistics, squeezing, and entanglement are studied. The entanglement of these states is examined by calculating the concurrence. According to our calculations, three of the introduced states are maximally entangled states. In addition, the cross-correlation function of the three maximally entangled states is less than 1 for all values of |α|2.