Unruh acceleration effect on the precision of parameter estimation (original) (raw)
Related papers
Quantum Fisher information of fermionic cavity modes in an accelerated motion
We investigate the effect of the inertial and non-inertial segments of relativistic motion on the quantum Fisher information of (1+1) Dirac field modes confined to cavities. %For this purpose, a bipartite system comprising of Alice's and Rob's cavities with appropriate boundary conditions is prepared. For the purpose, we consider the situation that Rob's cavity, initially inertial, accelerates uniformly with respect to its proper time and then again becomes inertial while Alice's cavity remains inertial. The acceleration is assumed to be very small and its effects were analyzed in a perturbative regime. For analysis, we consider theta\thetatheta parameterized two-qubit pure entangled state and a Werner state. In contrast to the degradation of entanglement due to the relativistic motion between the cavities, the quantum Fisher information of the pure composite system mathcalFtheta\mathcal{F}_\thetamathcalFtheta with respect to parameter theta\thetatheta is found to be invariant under the same conditions. Ho...
Physics, 2019
We have investigated numerically the dynamics of quantum Fisher information (QFI) and quantum entanglement (QE) of a two moving two-level atomic systems interacting with a coherent and thermal field in the presence of intrinsic decoherence (ID) and Kerr (non-linear medium) and Stark effects. The state of the entire system interacting with coherent and thermal fields is evaluated numerically under the influence of intrinsic decoherence (ID) and Kerr (nonlinear) and Stark effects. Quantum Fisher information and von Neumann entropy decreases in the presence of intrinsic decoherence when the atomic motion is neglected. Quantum Fisher information (QFI) and QE show an opposite response during its time evolution in the presence of a thermal environment. Quantum Fisher information is found to be more susceptible to intrinsic decoherence (ID) as compared to quantum entanglement (QE) in the presence of a thermal environment. The decay of QE is further damped at greater time-scales, which conf...
Fundamental limitations to information transfer in accelerated frames
2012
We study communication between an inertial observer and one of two causally-disconnected counter accelerating observers. We will restrict the quantum channel considering inertial-toaccelerated bipartite classical and quantum communication over different sets of Unruh modes (single-rail or dual-rail encoding). We find that the coherent information (and therefore, the amount of entanglement that can be generated via state merging protocol) in this strongly restricted channel presents some interesting monogamy properties between the inertial and only one of the accelerated observers if we take a fixed choice of the Unruh mode used in the channel. The optimization of the controllable parameters is also studied and we find that they deviate from the values usually employed in the literature.
Entanglement, QFI and squeezing of hybrid state in non-inertial frame Scientific research paper
JITL, 2022
We study the effect of acceleration of the observer on the quantum Fisher information and entanglement using hybrid state. The two-partite entangled hybrid state is consisted of discrete (vacuum and single photon) and continues (coherent) variable states. When one of the observers (e.g., Rob) is uniformly accelerated with respect to the other partner, Alice, we find that quantum Fisher information has a more stable structure than entanglement. Results show that quantum Fisher information decreases with the increase of the acceleration but remains finite in the limit of infinite acceleration that is in contrast with entanglement. Moreover, the effect of acceleration is investigated on the value of two-mode squeezing.
Detraction of decoherence that arises from the acceleration process
Journal of the Optical Society of America B
The possibility of detracting decoherence due to the acceleration process of the two-qutrit system was investigated, where we examined the behavior of relative entropy and non-local information. For this purpose, accelerated subsystems are allowed to pass through local or global noisy channels. It is shown that the detraction potential depends on the type of used noisy channel, local or global, and the initial settings of the accelerated qutrit systems, whether prepared in free or bound entangled intervals. The improvement rate depicted for systems prepared in free entangled intervals is much better than those prepared in bound entangled intervals. The maximum bounds of non-local information in the presence of amplitude damping channels are larger than those passed in the dephasing channel.
Entanglement entropy and the determination of an unknown quantum state
Physical Review a, 2008
An initial unknown quantum state can be determined with a single measurement apparatus by letting it interact with an auxiliary, "Ancilla", system as proposed by Allahverdyan, Balian and Nieuwenhuizen [Phys. Rev. Lett. 92, 120402 (2004)]. In the case of two qubits, this procedure allows to reconstruct the initial state of the qubit of interest S by measuring three commuting observables and therefore by means of a single apparatus, for the total system S + A at a later time. The determinant of the matrix of the linear transformation connecting the measurements of three commuting observables at time t > 0 to the components of the polarization vector of S at time t = 0 is used as an indicator of the reconstructability of the initial state of the system S. We show that a connection between the entanglement entropy of the total system S + A and such a determinant exists, and that for a pure state a vanishing entanglement individuates, without a need for any measurement, those intervals of time for which the reconstruction procedure is least efficient. This property remains valid for a generic dimension of S. In the case of a mixed state this connection is lost.
Empirical state determination of entangled two-level systems and its relation to information theory
1999
Theoretical methods for empirical state determination of entangled two-level systems are analyzed in relation to information theory. We show that hidden variable theories would lead to a Shannon index of correlation between the entangled subsystems which is larger than that predicted by quantum mechanics. Canonical representations which have maximal correlations are treated by the use of Schmidt decomposition of the entangled states, including especially the Bohm singlet state and the GHZ entangled states. We show that quantum mechanics does not violate locality, but does violate realism.
Decoherence, Anti-Decoherence, and Fisher Information
Entropy, 2021
In this work, we study quantum decoherence as reflected by the dynamics of a system that accounts for the interaction between matter and a given field. The process is described by an important information geometry tool: Fisher’s information measure (FIM). We find that it appropriately describes this concept, detecting salient details of the quantum–classical changeover (qcc). A good description of the qcc report can thus be obtained; in particular, a clear insight into the role that the uncertainty principle (UP) plays in the pertinent proceedings is presented. Plotting FIM versus a system’s motion invariant related to the UP, one can also visualize how anti-decoherence takes place, as opposed to the decoherence process studied in dozens of papers. In Fisher terms, the qcc can be seen as an order (quantum)–disorder (classical, including chaos) transition.
Entanglement dynamics between inertial and non-uniformly accelerated detectors
Journal of High Energy Physics, 2012
We study the time-dependence of quantum entanglement between two Unruh-DeWitt detectors, one at rest in a Minkowski frame, the other non-uniformly accelerated in some specified way. The two detectors each couple to a scalar quantum field but do not interact directly. The primary challenge in problems involving non-uniformly accelerated detectors arises from the fact that an event horizon is absent and the Unruh temperature is ill-defined. By numerical calculation we demonstrate that the correlators of the accelerated detector in the weak coupling limit behaves like those of an oscillator in a bath of time-varying "temperature" proportional to the instantaneous proper acceleration of the detector, with oscillatory modifications due to non-adiabatic effects. We find that in this setup the acceleration of the detector in effect slows down the disentanglement process in Minkowski time due to the time dilation in that moving detector.
Entanglement entropy and determination of an unknown quantum state
Physical Review A, 2008
An initial unknown quantum state can be determined with a single measurement apparatus by letting it interact with an auxiliary, "Ancilla", system as proposed by Allahverdyan, Balian and Nieuwenhuizen [Phys. Rev. Lett. 92, 120402 (2004)]. In the case of two qubits, this procedure allows to reconstruct the initial state of the qubit of interest S by measuring three commuting observables and therefore by means of a single apparatus, for the total system S + A at a later time. The determinant of the matrix of the linear transformation connecting the measurements of three commuting observables at time t > 0 to the components of the polarization vector of S at time t = 0 is used as an indicator of the reconstructability of the initial state of the system S. We show that a connection between the entanglement entropy of the total system S + A and such a determinant exists, and that for a pure state a vanishing entanglement individuates, without a need for any measurement, those intervals of time for which the reconstruction procedure is least efficient. This property remains valid for a generic dimension of S. In the case of a mixed state this connection is lost.