scholarly journals Characterization of quantum and classical correlations in the Earth’s curved space-time

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tonghua Liu ◽  
Shuo Cao ◽  
Shumin Wu
Keyword(s):  
Relativistic Effects ◽  
Quantum Correlations ◽  
Space Time ◽  
Kerr Metric ◽  
Curved Space ◽  
The Earth ◽  
Rotation Of The Earth ◽  
Earth Orbits ◽  
Quantum And Classical Correlations

Abstract The preparation of quantum systems and the execution of quantum information tasks between distant users are always affected by gravitational and relativistic effects. In this work, we quantitatively analyze how the curved space-time background of the Earth affects the classical and quantum correlations between photon pairs that are initially prepared in a two-mode squeezed state. More specifically, considering the rotation of the Earth, the space-time around the Earth is described by the Kerr metric. Our results show that these state correlations, which initially increase for a specific range of satellite’s orbital altitude, will gradually approach a finite value with increasing height of satellite’s orbit (when the special relativistic effects become relevant). More importantly, our analysis demonstrates that the changes of correlations generated by the total gravitational frequency shift could reach the level of $$<0.5\%$$ < 0.5 % within the satellite’s height at geostationary Earth orbits.

THERMAL DISCORD AND NEGATIVITY IN A TWO-SPIN-QUTRIT SYSTEM UNDER DIFFERENT MAGNETIC FIELDS

2013 ◽  
Vol 11 (08) ◽  
pp. 1350070 ◽  
Author(s):  
XIAO-JING LI ◽  
HUI-HUI JI ◽  
XI-WEN HOU
Keyword(s):  
Magnetic Fields ◽  
Quantum Discord ◽  
Strong Field ◽  
Quantum Correlations ◽  
Mixed States ◽  
Classical Correlation ◽  
Lower Temperature ◽  
Qubit States ◽  
Quantum And Classical Correlations

The characterization of quantum discord (QD) has been well understood only for two-qubit states and is little known for mixed states beyond qubits. In this work, thermal quantum discord is studied for a qutrit system in different magnetic fields, where classical correlation and entanglement negativity are calculated for comparison. It is shown that the discord is more robust against temperature than the negativity. For a suitable region of magnetic field and its direction, the discord is non-zero while the negativity is zero. When the system is at a lower temperature, these three quantities, however, display a similar behavior for the varied field and direction, and their discontinuities come from crossovers between different ground states in the system. Moreover, the inequality between the quantum and classical correlations depends upon the system parameters as well as the temperature. In particular, both correlations are equal at a suitable field, direction, and temperature. Remarkably, such an equality remains for a strong field in the antiparallel direction, while both correlations in two-qubit systems are identical for any antiparallel field and temperature. These are useful for quantum information and understanding quantum correlations in qutrit mixed states.

scholarly journals Antimatter Gravity: Second Quantization and Lagrangian Formalism

Physics ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 397-411
Author(s):  
Ulrich D. Jentschura
Keyword(s):  
Dirac Equation ◽  
Flat Space ◽  
Space Time ◽  
Charge Conjugation ◽  
Lagrangian Formalism ◽  
Curved Space ◽  
The Earth ◽  
Antimatter Gravity ◽  
Quantized Field ◽  
Charge Conjugation Parity

The application of the CPT (charge-conjugation, parity, and time reversal) theorem to an apple falling on Earth leads to the description of an anti-apple falling on anti–Earth (not on Earth). On the microscopic level, the Dirac equation in curved space-time simultaneously describes spin-1/2 particles and their antiparticles coupled to the same curved space-time metric (e.g., the metric describing the gravitational field of the Earth). On the macroscopic level, the electromagnetically and gravitationally coupled Dirac equation therefore describes apples and anti-apples, falling on Earth, simultaneously. A particle-to-antiparticle transformation of the gravitationally coupled Dirac equation therefore yields information on the behavior of “anti-apples on Earth”. However, the problem is exacerbated by the fact that the operation of charge conjugation is much more complicated in curved, as opposed to flat, space-time. Our treatment is based on second-quantized field operators and uses the Lagrangian formalism. As an additional helpful result, prerequisite to our calculations, we establish the general form of the Dirac adjoint in curved space-time. On the basis of a theorem, we refute the existence of tiny, but potentially important, particle-antiparticle symmetry breaking terms in which possible existence has been investigated in the literature. Consequences for antimatter gravity experiments are discussed.

Celestial Reference Systems Derivable from Solar System Dynamics

1975 ◽  
Vol 26 ◽  
pp. 223-233 ◽  
Author(s):  
R. L. Duncombe ◽  
P. K. Seidelmann ◽  
T. C. Van Flandern
Keyword(s):  
Solar System ◽  
System Dynamics ◽  
Coordinate System ◽  
Relativistic Effects ◽  
System A ◽  
The Earth ◽  
Rotation Of The Earth ◽  
Celestial Sphere ◽  
Solar System Dynamics ◽  
System Selection

AbstractSolar system dynamics define a number of planes which could be the basis of a coordinate system. The equatorial, ecliptic, invariant, and planetary orbit planes are compared to an inertial coordinate system. Selection of a fiducial point requires consideration of precession and equinox motion and the relationships between the coordinate system of the celestial sphere, observed hour angles and the terrestrial longitude system. A time system might be based on the rotation of the Earth, the motion of the Sun, Moon and planets, or some nondynamical repetitive phenomena. Consideration must be given to the difficulties of the various systems, such as the irregrular rotation of the Earth, the uncertain tidal friction and anomalies of the Moon’s motion, the rapidity and accuracy of time determination-, and relativistic effects.

VII.—On the Measurement of Spatial Distance in a Curved Space-time

1934 ◽  
Vol 53 ◽  
pp. 79-88 ◽  
Author(s):  
H. S. Ruse
Keyword(s):  
Riemannian Space ◽  
Space Time ◽  
Present Writer ◽  
Spatial Distance ◽  
Curved Space ◽  
The Earth ◽  
The Given

The problem of defining the concept of spatial distance in a general riemannian space-time has been discussed by E. T. Whittaker, who showed how to translate into the terms of four-dimensional geometry the method adopted by astronomers in determining the distance of a star from the earth by means of a comparison of its absolute and apparent luminosities. The problem was further considered by the present writer, who derived a different formula for spatial distance by a method which was essentially one of partitioning the whole of space-time into space and time relative to the given observer. It was suggested that the new spatial distance might be that determined practically by parallax-measurements, though the evidence in support of this suggestion was perhaps hardly sufficient to carry conviction.

An Interview with the Physicist that Her Head in the Universe and Both Feet on the Earth

2019 ◽  
Author(s):  
Adib Rifqi Setiawan
Keyword(s):  
Standard Model ◽  
Particle Physics ◽  
Space Time ◽  
Additional Dimension ◽  
The Earth ◽  
The Standard Model ◽  
The Universe

Put simply, Lisa Randall’s job is to figure out how the universe works, and what it’s made of. Her contributions to theoretical particle physics include two models of space-time that bear her name. The first Randall–Sundrum model addressed a problem with the Standard Model of the universe, and the second concerned the possibility of a warped additional dimension of space. In this work, we caught up with Randall to talk about why she chose a career in physics, where she finds inspiration, and what advice she’d offer budding physicists. This article has been edited for clarity. My favourite quote in this interview is, “Figure out what you enjoy, what your talents are, and what you’re most curious to learn about.” If you insterest in her work, you can contact her on Twitter @lirarandall.

An Interview with the Physicist that Her Head in the Universe and Both Feet on the Earth

2019 ◽  
Author(s):  
Adib Rifqi Setiawan
Keyword(s):  
Standard Model ◽  
Particle Physics ◽  
Space Time ◽  
Additional Dimension ◽  
The Earth ◽  
The Standard Model ◽  
The Universe

Put simply, Lisa Randall’s job is to figure out how the universe works, and what it’s made of. Her contributions to theoretical particle physics include two models of space-time that bear her name. The first Randall–Sundrum model addressed a problem with the Standard Model of the universe, and the second concerned the possibility of a warped additional dimension of space. In this work, we caught up with Randall to talk about why she chose a career in physics, where she finds inspiration, and what advice she’d offer budding physicists. This article has been edited for clarity. My favourite quote in this interview is, “Figure out what you enjoy, what your talents are, and what you’re most curious to learn about.” If you insterest in her work, you can contact her on Twitter @lirarandall.

Path integrals and the solution of the Schwinger model in curved space-time

1986 ◽  
Vol 33 (8) ◽  
pp. 2262-2266 ◽  
Author(s):  
J. Barcelos-Neto ◽  
Ashok Das
Keyword(s):  
Path Integrals ◽  
Space Time ◽  
Curved Space ◽  
Schwinger Model
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