Probing macroscopic quantum states with a sub-Heisenberg accuracy

Journal Article · Fri Jan 15 00:00:00 EST 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.81.012114· OSTI ID:21388683

Haixing, Miao ^[1]; Danilishin, Stefan ^[2]; Mueller-Ebhardt, Helge; Rehbein, Henning ^[3]; Somiya, Kentaro; Yanbei, Chen ^[4]

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1. School of Physics, University of Western Australia, Western Australia 6009 (Australia)
2. Physics Faculty, Moscow State University, Moscow RU-119991 (Russian Federation)
3. Max-Planck Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Leibniz Universitaet Hannover, Callinstrasse 38, D-30167 Hannover (Germany)
4. Theoretical Astrophysics 130-33, California Institute of Technology, Pasadena, California 91125 (United States)

Significant achievements in high-sensitivity measurements will soon allow us to probe quantum behaviors of macroscopic mechanical oscillators. In a recent work [Phys. Rev. A 80, 043802 (2009)], we formulated a general framework for treating preparation of Gaussian quantum states of macroscopic oscillators through linear position measurements. To outline a complete procedure for testing macroscopic quantum mechanics, here we consider a subsequent verification stage which probes the prepared macroscopic quantum state and verifies the quantum dynamics. By adopting an optimal time-dependent homodyne detection in which the phase of the local oscillator varies in time, the conditional quantum state can be characterized below the Heisenberg limit, thereby achieving a quantum tomography. In the limiting case of no readout loss, such a scheme evades measurement-induced back action, which is identical to the variational-type measurement scheme invented by Vyatchanin et al. [JETP 77, 218 (1993)] but in the context for detecting gravitational waves. To motivate macroscopic quantum mechanics experiments with future gravitational-wave detectors, we mostly focus on the parameter regime where the characteristic measurement frequency is much higher than the oscillator frequency and the classical noises are Markovian, which captures the main feature of a broadband gravitational-wave detector. In addition, we discuss verifications of Einstein-Podolsky-Rosen-type entanglement between macroscopic test masses in future gravitational-wave detectors, which enables us to test one particular version of gravity decoherence conjectured by Diosi [Phys. Lett. A120, 377 (1987)] and Penrose [Gen. Rel. Grav. 28, 581 (1996)].

• OSTI ID: 21388683
• Journal Information: Physical Review. A, Vol. 81, Issue 1; Other Information: DOI: 10.1103/PhysRevA.81.012114; (c) 2010 The American Physical Society; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCURACY
CAPTURE
DETECTION
GRAVITATION
GRAVITATIONAL WAVE DETECTORS
GRAVITATIONAL WAVES
MARKOV PROCESS
MASS
NOISE
OSCILLATORS
QUANTUM ENTANGLEMENT
QUANTUM MECHANICS
READOUT SYSTEMS
SENSITIVITY
TESTING
TIME DEPENDENCE
TOMOGRAPHY
VARIATIONAL METHODS
VERIFICATION
CALCULATION METHODS
DIAGNOSTIC TECHNIQUES
ELECTRONIC EQUIPMENT
EQUIPMENT
MEASURING INSTRUMENTS
MECHANICS
RADIATION DETECTORS
STOCHASTIC PROCESSES