Quantum Limits to the Measurement of Spacetime Geometry
Seth Lloyd Massachusetts Institute of Technology (MIT) - Center for Extreme Quantum Information Theory (xQIT)
PIRSA:12060061
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A Fully-Relativistic Bandlimit on Quantum Fields' Two-Point Correlation Functions
Aidan Chatwin-Davies University of British Columbia
PIRSA:12060041 -
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Measuring Distance with Acceleration-assisted Entanglement Harvesting
Grant Salton Amazon.com
PIRSA:12060059 -
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Black Hole Entrophy Related to Measures of Entanglement
Peter Levay Budapest University of Technology and Economics
PIRSA:12060039 -
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Towards Quantum Science Experiments with Satellites
Thomas Jennewein Institute for Quantum Computing (IQC)
PIRSA:12060057 -
Relativistic Quantum Information anRelativistic Quantum Optics: towards experiments to reveal quantum effects provoked by gravity
Eduardo Martin-Martinez University of Waterloo
PIRSA:12060043 -
On-chip Extraction of Quantum Correlations from the Vacuum
PIRSA:12060056 -
Entanglement Resonances
PIRSA:12060055 -
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Quantum Limits to the Measurement of Spacetime Geometry
Seth Lloyd Massachusetts Institute of Technology (MIT) - Center for Extreme Quantum Information Theory (xQIT)
PIRSA:12060061This talk analyzes the limits that quantum mechanics imposes on the accuracy to which spacetime geometry can be measured. By applying the fundamental physical bounds to measurement accuracy ensembles of clocks and signals, as in the global positioning system, I present a covariant version of the quantum geometric limit, which states that the total number of ticks of clocks and clicks of detectors that can be contained in a four volume of spacetime of radius R and temporal extent is less than or equal to RT divided by the Planck length times the Planck time. The quantum geometric bound limits the number of events or `ops' that can take place in a four-volume of spacetime and is consistent with and complementary to the holographic bound which limits the number of bits that can exist within a three-volume of spacetime. -
A Fully-Relativistic Bandlimit on Quantum Fields' Two-Point Correlation Functions
Aidan Chatwin-Davies University of British Columbia
PIRSA:12060041The bridge between continuous information and discrete information is provided by sampling theory. In this talk, I will discuss an application of covariant sampling theory to cosmology (see the previous talk by Dr. R. Martin). In cosmology, the two-point correlation function of a quantum field is of central importance because it is a measure of the size of the fluctuations of the quantum field and of the entanglement of the vacuum in a given spacetime. Furthermore, the two-point function is experimentally accessible through the cosmic microwave background. Using covariant sampling theory, I will show how an information-theoretic bandlimit imposed at the Planck scale manifests itself in the two-point function. We will examine this bandlimit in Minkowski space and in de Sitter space. -
A Fully Covariant Information Theoretic Ultraviolet Cutoff for Fields on Expanding FRW Spacetimes
PIRSA:12060060A covariant ultra-violet cutoff on the modes of physical fields on a given space-time can be achieved by cutting off the spectrum of the D'Alembertian of the manifold. This cutoff is a natural generalization of the naive ultra-violet cutoff inEuclidean space which is obtained by simply projecting out frequencies greater in magnitude than a given maximum frequency. Here it is shown that for flat spacetime and expanding FRW spacetimes thiscutoff manifests itself as a decrease in temporal degrees of freedom for large spatial modes. In a large class of expanding FRW spacetimes where the proper time co-ordinate ends at a finite value, it is shown how the numberof temporal degrees of freedom of a fixed spatial mode depends on the magnitude of the spatial mode. We further indicate how the effects of this ultra-violet cutoff on the dynamics of field theories can be studied, and how the resulting modifications to inflationary predictions of the CMB spectrum could be calculated. This talk is based on ongoing joint work with Prof. Achim Kempf (University of Waterloo) and Aidan Chatwin-Davies (UW). -
Measuring Distance with Acceleration-assisted Entanglement Harvesting
Grant Salton Amazon.com
PIRSA:12060059We show that entanglement harvested from a quantum field by interaction with local detectors undergoing anti-parallel acceleration can be used to measure the distance of closest approach between the two detectors. Information about the separation is stored nonlocally in the phase of the joint state of the detectors after the interaction; a single detector alone contains none. We model the detectors as two-level quantum systems accelerating uniformly through the Minkowski vacuum while interacting for a short time with a massless scalar field. This interaction allows entanglement to be swapped locally from the field to the detectors. Although each detector alone sees the same thermal spectrum (due to Unruh radiation), the joint state between them may be entangled. In the vicinity of a critical distance of closest approach between the detectors, the phase of the entangled state depends sensitively on the distance. We contrast this with the case of parallel acceleration, in which no such critical distance exists, and we discuss the connection of this case with entanglement harvested from an expanding universe. -
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Black Hole Entrophy Related to Measures of Entanglement
Peter Levay Budapest University of Technology and Economics
PIRSA:12060039Recently striking connections have been discovered between the research fields of black hole soultions in string theory and the one of entanglement measures in quantum entanglement theory.For the emerging research field the term The Black Hole/Qubit Correspondence has been coined. The basic idea is that wrapping configurations of extended objects in extra dimensions can give rise to interesting realizations of entangled systems and black holes at the same time. The geometry of the extra dimensions and the wrapping type determines the entangled system in question. Usually as the extra dimensional spaces Calabi-Yau manifolds are chosen. In this talk I give some hints how this constraint could be relaxed. These considerations might substantially generalize the range of validity of the Black-Hole/Qubit correspondence. -
Black Holes and Qubits
Michael Duff Imperial College London
PIRSA:12060038Two different branches of theoretical physics, string theory and quantum information theory (QIT), share many of the same features, allowing knowledge on one side to provide new insights on the other. In particular the matching of the classification of stringy black holes and the classification of four-qubit entanglement provides a falsifiable prediction in the field of QIT. -
Towards Quantum Science Experiments with Satellites
Thomas Jennewein Institute for Quantum Computing (IQC)
PIRSA:12060057Space offers a very unique environment for quantum physics experiments at regimes for distance and velocity not possible on ground. In the recent years there have been a range of theoretical and experimental studies towards the feasibility of performing quantum physics and quantum information science experiments in space. The most advanced quantum application is quantum cryptography, known as quantum key distribution (QKD), which can be extended to global distances by bringing suitable quantum systems into space. It is interesting to note that with quantum satellites in Earth's orbit, we will be able to perform tests on the validity of quantum physics and entanglement at huge length scales and velocities. This could provide a possible route towards gaining insights into the interplay of quantum physics and relativity. I will review some of the interesting quantum entanglement tests that can be performed with satellites in space. I will also outline a proposed satellite mission that is based on existing technology on a small-scale satellite, and could be a first important step into this direction. -
Relativistic Quantum Information anRelativistic Quantum Optics: towards experiments to reveal quantum effects provoked by gravity
Eduardo Martin-Martinez University of Waterloo
PIRSA:12060043We will explore different results on relativistic quantum information and general relativistic quantum optics whose aim is to provide scenarios where relativistic quantum effects can be experimentally accessible. Traditionally, relativistic quantum information has been far away from the experimental test, but the discipline is close to the transition point where experimental outcomes will soon arise. Not only to bestow experimental proof on long ago predicted but still undetected phenomena (such as the Unruh and Hawking effects), but also to provide insight into the relationship of general relativity and quantum theory, and to serve as a source of new quantum technologies.
We will show how it is possible to extract timelike and spacelike quantum correlations from the vacuum state of the field in a tabletop experiment, and how to use it to build a quantum memory. We will see how geometric phases can help to detect the Unruh effect and how to use what we learn from that setting to build a quantum thermometer. Finally we will discuss how quantum simulators can be applied to the study of quantum effects of gravity, and used to predict experimental scenarios way beyond current computational power of classical computers. -
On-chip Extraction of Quantum Correlations from the Vacuum
PIRSA:12060056 -
Entanglement Resonances
PIRSA:12060055We investigate entanglement creation between modes of a quantum field contained within a cavity which undergoes noninertial motion. We find that, in the the low acceleration regime, or equivalently in the small cavity regime, entanglement can be created from initially separable states and it can be linearly increased by repeating travel scenarios. We are able to fin analytically how all the parameter involved affect the entanglement. We suggest that this can be of interest when looking for experimental veriications of predictions within the field of relativistic quantum information.
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