1
|
Laha P, Moore DW, Filip R. Entanglement Growth via Splitting of a Few Thermal Quanta. PHYSICAL REVIEW LETTERS 2024; 132:210201. [PMID: 38856241 DOI: 10.1103/physrevlett.132.210201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 02/20/2024] [Accepted: 04/08/2024] [Indexed: 06/11/2024]
Abstract
Quanta splitting is an essential generator of Gaussian entanglement, exemplified by Einstein-Podolsky-Rosen states and apparently the most commonly occurring form of entanglement. In general, it results from the strong pumping of a nonlinear process with a highly coherent and low-noise external drive. In contrast, recent experiments involving efficient trilinear processes in trapped ions and superconducting circuits have opened the complementary possibility to test the splitting of a few thermal quanta. Stimulated by such small thermal energy, a strong degenerate trilinear coupling generates large amounts of nonclassicality, detectable by more than 3 dB of distillable quadrature squeezing. Substantial entanglement can be generated via frequent passive linear coupling to a third mode present in parallel with the trilinear coupling. This new form of entanglement, outside any Gaussian approximation, surprisingly grows with the mean number of split thermal quanta; a quality absent from Gaussian entanglement. Using distillable squeezing we shed light on this new entanglement mechanism for nonlinear bosonic systems.
Collapse
Affiliation(s)
- Pradip Laha
- Department of Optics, Palacký University, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
| | - Darren W Moore
- Department of Optics, Palacký University, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
| | - Radim Filip
- Department of Optics, Palacký University, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
| |
Collapse
|
2
|
Laha P, Slodička L, Moore DW, Filip R. Thermally induced entanglement of atomic oscillators. OPTICS EXPRESS 2022; 30:8814-8828. [PMID: 35299326 DOI: 10.1364/oe.449811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
Laser cooled ions trapped in a linear Paul trap are long-standing ideal candidates for realizing quantum simulation, especially of many-body systems. The properties that contribute to this also provide the opportunity to demonstrate unexpected quantum phenomena in few-body systems. A pair of ions interacting in such traps exchange vibrational quanta through the Coulomb interaction. This linear interaction can be anharmonically modulated by an elementary coupling to the internal two-level structure of one of the ions. Driven by thermal energy in the passively coupled oscillators, which are themselves coupled to the internal ground states of the ions, the nonlinear interaction autonomously and unconditionally generates entanglement between the mechanical modes of the ions. We examine this counter-intuitive thermally induced entanglement for several experimentally feasible model systems and propose parameter regimes where state-of-the-art trapped ion systems can produce such phenomena. In addition, we demonstrate a multiqubit enhancement of such thermally induced entanglements.
Collapse
|
3
|
Tavis-Cummings Model with Moving Atoms. ENTROPY 2021; 23:e23040452. [PMID: 33921240 PMCID: PMC8068796 DOI: 10.3390/e23040452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/27/2021] [Accepted: 04/02/2021] [Indexed: 11/16/2022]
Abstract
In this work, we examine a nonlinear version of the Tavis–Cummings model for two two-level atoms interacting with a single-mode field within a cavity in the context of power-law potentials. We consider the effect of the particle position that depends on the velocity and acceleration, and the coupling parameter is supposed to be time-dependent. We examine the effect of velocity and acceleration on the dynamical behavior of some quantumness measures, namely as von Neumann entropy, concurrence and Mandel parameter. We have found that the entanglement of subsystem states and the photon statistics are largely dependent on the choice of the qubit motion and power-law exponent. The obtained results present potential applications for quantum information and optics with optimal conditions.
Collapse
|
4
|
Symmetry in the open-system dynamics of quantum correlations. Sci Rep 2017; 7:8367. [PMID: 28827609 PMCID: PMC5566315 DOI: 10.1038/s41598-017-08457-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 07/10/2017] [Indexed: 11/16/2022] Open
Abstract
We study the symmetry properties in the dynamics of quantum correlations for two-qubit systems in one-sided noisy channels, with respect to a switch in the location of noise from one qubit to the other. We consider four different channel types, namely depolarizing, amplitude damping, bit-flip, and bit-phase-flip channel, and identify the classes of initial states leading to symmetric decay of entanglement, non-locality and discord. Our results show that the symmetric decay of quantum correlations is not directly linked to the presence or absence of symmetry in the initial state, while it does depend on the type of correlation considered as well as on the type of noise. We prove that asymmetric decay can be used to infer, in certain cases, characteristic properties of the channel. We also show that the location of noise may lead to dramatic changes in the persistence of phenomena such as entanglement sudden death and time-invariant discord.
Collapse
|
5
|
Brezinski ME, Rupnick M. Can We Advance Macroscopic Quantum Systems Outside the Framework of Complex Decoherence Theory? JOURNAL OF COMPUTER SCIENCE AND SYSTEMS BIOLOGY 2014; 7:119-136. [PMID: 29200743 PMCID: PMC5710819 DOI: 10.4172/jcsb.1000147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Macroscopic quantum systems (MQS) are macroscopic systems driven by quantum rather than classical mechanics, a long studied area with minimal success till recently. Harnessing the benefits of quantum mechanics on a macroscopic level would revolutionize fields ranging from telecommunication to biology, the latter focused on here for reasons discussed. Contrary to misconceptions, there are no known physical laws that prevent the development of MQS. Instead, they are generally believed universally lost in complex systems from environmental entanglements (decoherence). But we argue success is achievable MQS with decoherence compensation developed, naturally or artificially, from top-down rather current reductionist approaches. This paper advances the MQS field by a complex systems approach to decoherence. First, why complex system decoherence approaches (top-down) are needed is discussed. Specifically, complex adaptive systems (CAS) are not amenable to reductionist models (and their master equations) because of emergent behaviour, approximation failures, not accounting for quantum compensatory mechanisms, ignoring path integrals, and the subentity problem. In addition, since MQS must exist within the context of the classical world, where rapid decoherence and prolonged coherence are both needed. Nature has already demonstrated this for quantum subsystems such as photosynthesis and magnetoreception. Second, we perform a preliminary study that illustrates a top-down approach to potential MQS. In summary, reductionist arguments against MQS are not justifiable. It is more likely they are not easily detectable in large intact classical systems or have been destroyed by reductionist experimental set-ups. This complex systems decoherence approach, using top down investigations, is critical to paradigm shifts in MQS research both in biological and non-biological systems.
Collapse
Affiliation(s)
- Mark E Brezinski
- Center for Optical Coherence Tomography and Modern Physics, Department of Orthopedic Surgery, Brigham and Women’s Hospital, 75 Francis Street, MRB-114, Boston, MA 02115, USA
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Rm 36-360, 50 Vassar St., Cambridge, MA 02139, USA
| | - Maria Rupnick
- Center for Optical Coherence Tomography and Modern Physics, Department of Orthopedic Surgery, Brigham and Women’s Hospital, 75 Francis Street, MRB-114, Boston, MA 02115, USA
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA
| |
Collapse
|
6
|
Brezinski ME, Liu B. Nonlocal quantum macroscopic superposition in a high-thermal low-purity state. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 2008; 78:10.1103/PhysRevA.78.063824. [PMID: 24204102 PMCID: PMC3818030 DOI: 10.1103/physreva.78.063824] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Quantum state exchange between light and matter is an important ingredient for future quantum information networks as well as other applications. Photons are the fastest and simplest carriers of information for transmission but in general, it is difficult to localize and store photons, so usually one prefers choosing matter as quantum memory elements. Macroscopic superposition and nonlocal quantum interactions have received considerable interest for this purpose over recent years in fields ranging from quantum computers to cryptography, in addition to providing major insights into physical laws. However, these experiments are generally performed either with equipment or under conditions that are unrealistic for practical applications. Ideally, the two can be combined using conventional equipment and conditions to generate a "quantum teleportation"-like state, particularly with a very small amount of purity existing in an overall highly mixed thermal state (relatively low decoherence at high temperatures). In this study we used an experimental design to demonstrate these principles. We performed optical coherence tomography (OCT) using a thermal source at room temperatures of a specifically designed target in the sample arm. Here, position uncertainty (i.e., dispersion) was induced in the reference arm. In the sample arm (target) we placed two glass plates separated by a different medium while altering position uncertainty in the reference arm. This resulted in a chirped signal between the glass plate reflective surfaces in the combined interferogram. The chirping frequency, as measured by the fast Fourier transform (FFT), varies with the medium between the plates, which is a nonclassical phenomenon. These results are statistically significant and occur from a superposition between the glass surface and the medium with increasing position uncertainty, a true quantum-mechanical phenomenon produced by photon pressure from two-photon interference. The differences in chirping frequency with medium disappears when second-order correlations are removed by dual balanced detection, confirming the proposed mechanism. We demonstrated that increasing position uncertainty at one site leads to position uncertainty (quantum position probability amplitude) nonlocally via second-order correlations (two-photon probability amplitude) from a low coherence thermal source (low purity, high local entropy). The implications, first, are that the phenomenon cannot be explained through classical mechanisms but can be explained within the context of quantum mechanics, particularly relevant to the second-order correlations where controversy exists. More specifically, we provide the theoretical framework that these results indicate a nonlocal macroscopic superposition is occurring through a two-photon probability amplitude-induced increase in the target position probability amplitude uncertainty. In addition, as the experiments were performed with a classical source at room temperature, it supports both the quantum-mechanical properties of second-order correlations and that macroscopic superposition is obtainable in a target not in a single coherent state (mixed state). Future work will focus on generalizing the observations outside the current experimental design and creating embodiments that allow practical application of the phenomenon.
Collapse
Affiliation(s)
- Mark E. Brezinski
- Center for Optical Coherence Tomography and Optical Physics, Department
of Orthopedic Surgery, Brigham and Women’s Hospital, 75 Francis Street,
Boston, Massachusetts 02115, USA and Harvard Medical School, 25 Shattuck Street,
Boston, Massachusetts 02115, USA
| | - Bin Liu
- Center for Optical Coherence Tomography and Optical Physics, Department
of Orthopedic Surgery, Brigham and Women’s Hospital, 75 Francis Street,
Boston, Massachusetts 02115, USA and Harvard Medical School, 25 Shattuck Street,
Boston, Massachusetts 02115, USA
| |
Collapse
|
7
|
Jeong H, Ralph TC. Transfer of nonclassical properties from a microscopic superposition to macroscopic thermal states in the high temperature limit. PHYSICAL REVIEW LETTERS 2006; 97:100401. [PMID: 17025793 DOI: 10.1103/physrevlett.97.100401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Indexed: 05/12/2023]
Abstract
We present several examples where prominent quantum properties are transferred from a microscopic superposition to thermal states at high temperatures. Our work is motivated by an analogy of Schrödinger's cat paradox, where the state corresponding to the virtual cat is a mixed thermal state with a large average photon number. Remarkably, quantum entanglement can be produced between thermal states with nearly the maximum Bell-inequality violation even when the temperatures of both modes approach infinity.
Collapse
Affiliation(s)
- Hyunseok Jeong
- Department of Physics, University of Queensland, St Lucia, Qld 4072, Australia.
| | | |
Collapse
|
8
|
Lee J, Paternostro M, Kim MS, Bose S. Entanglement reciprocation between qubits and continuous variables. PHYSICAL REVIEW LETTERS 2006; 96:080501. [PMID: 16606160 DOI: 10.1103/physrevlett.96.080501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Indexed: 05/08/2023]
Abstract
We investigate how entanglement can be transferred between qubits and continuous-variable (CV) systems. We find that one ebit borne in maximally entangled qubits can be fully transferred to two CV systems which are initially prepared in a pure separable Gaussian field with high excitation. We show that it is possible to retrieve the entanglement back to qubits from the entangled CV systems. The deposition of multiple ebits from qubits to the initially separable CV systems is also pointed out. We show that the entanglement transfer and retrieval are done at a quasisteady state.
Collapse
Affiliation(s)
- Jinhyoung Lee
- Department of Physics and Quantum Photonic Science Research Center, Hanyang University, Seoul 133-791, Korea
| | | | | | | |
Collapse
|
9
|
Ferreira A, Guerreiro A, Vedral V. Macroscopic thermal entanglement due to radiation pressure. PHYSICAL REVIEW LETTERS 2006; 96:060407. [PMID: 16605972 DOI: 10.1103/physrevlett.96.060407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2005] [Indexed: 05/08/2023]
Abstract
Can entanglement and the quantum behavior in physical systems survive at arbitrary high temperatures? In this Letter we show that this is the case for a electromagnetic field mode in an optical cavity with a movable mirror in a thermal state. We also identify two different dynamical regimes of generation of entanglement separated by a critical coupling strength.
Collapse
Affiliation(s)
- Aires Ferreira
- Faculdade Ciências Universidade do Porto, Rua do Campo Alegre 687 4169-007, Porto, Portugal
| | | | | |
Collapse
|
10
|
Eisert J, Plenio MB. Quantum and classical correlations in quantum Brownian motion. PHYSICAL REVIEW LETTERS 2002; 89:137902. [PMID: 12225064 DOI: 10.1103/physrevlett.89.137902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2001] [Revised: 06/21/2002] [Indexed: 05/23/2023]
Abstract
We investigate the entanglement properties of the joint state of a distinguished quantum system and its environment in the quantum Brownian motion model. This model is a frequent starting point for investigations of environment-induced superselection. Using recent methods from quantum information theory, we show that there exists a large class of initial states for which no entanglement will be created at all times between the system of salient interest and the environment. If the distinguished system has been initially prepared in a pure Gaussian state, then entanglement is created immediately, regardless of the temperature of the environment and the nonvanishing coupling.
Collapse
Affiliation(s)
- Jens Eisert
- QOLS, Blackett Laboratory, Imperial College of Science, Technology, and Medicine, London SW7 2BW, United Kingdom
| | | |
Collapse
|