Joakim Hallin - Academia.edu (original) (raw)
Papers by Joakim Hallin
Optillion AB c/o …, 2003
... Joakim Hallin2, Torgil Kjellberg2, Camilla Kärnfelt2, Bengt-Erik Olsson2, Magnus Andersson2, ... more ... Joakim Hallin2, Torgil Kjellberg2, Camilla Kärnfelt2, Bengt-Erik Olsson2, Magnus Andersson2, Herbert Zirath2, and Ulf Mattsson2,3 ... Concerning optical components, PIN photo diodes are available commercially with a bandwidth of 80 – 120 GHz (IPAG), but – to our knowledge ...
We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associate... more We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associated algebra of gauge-invariant functions, the T-variables. We solve the Mandelstam identities both classically and quantum-mechanically by considering the T-variables as functions of the eigenvalues of the holonomy and their associated momenta. It is shown that there are two inequivalent representations of the quantum T-algebra. Then we compare this reduced phase space approach to Dirac quantization and find it to give essentially equivalent results. We proceed to define a loop representation in each of these two cases. One of these loop representations (for N = 2) is more or less equivalent to the usual loop representation. 1
We report on advances in the OptCom-project within the fields of ultra high-speed electronics and... more We report on advances in the OptCom-project within the fields of ultra high-speed electronics and assembly technology. We highlight how we work towards our goal: a 100 Gbps transceiver demonstrator. Results of today include ICs from several generations of development. Our current best result is an IC operating at record-breaking 165 Gbps (serial bit stream). We will also outline our future activities towards more complex IC design, including electrical pseudo-random bit sequence generation and error detection at very high speed.
The kinematics of SL(2,R) Yang-Mills theory on a circle is considered, for reasons that are spell... more The kinematics of SL(2,R) Yang-Mills theory on a circle is considered, for reasons that are spelled out. The gauge transformations exhibit hyperbolic fixed points, and this results in a physical configuration space with a non-Hausdorff ”network” topology. The ambiguity encountered in canonical quantization is then much more pronounced than in the compact case, and can not be resolved through the kind of appeal made to group theory in that case. Email address: ingemar@vana.physto.se Email address: tfejh@fy.chalmers.se We have studied Yang-Mills theory on a cylindrical space-time, choosing the non-compact group SL(2,R) for our structure group. Since this undertaking may appear peculiar, we will begin by spelling out our motivation. First of all the Yang-Mills Hamiltonian is not positive definite whenever the structure group is non-compact. However, this is of no concern to us, since this operator will have nothing to do with the time-development of our model. Actually, we will not be ...
Next-generation mobile technology (5G) aims to provide an improved experience through higher data... more Next-generation mobile technology (5G) aims to provide an improved experience through higher data-rates, lower latency, and improved link robustness. Millimeter-wave phased arrays offer a path to support multiple users at high datarates using high-bandwidth directional links between the base station and mobile devices. To realize this vision, a phased-array-based pico-cell must support a large number of precisely controlled beams, yet be compact and power efficient. These system goals have significant mm-wave radio interface implications, including scalability of the RFIC+antenna-array solution, increase in the number of concurrent beams by supporting dual polarization, precise beam steering, and high output power without sacrificing TX power efficiency. Packaged Si-based phased arrays [1-3] with nonconcurrent dual-polarized TX and RX operation [2,3], concurrent dual-polarized RX operation [3] and multi-IC scaling [3,4] have been demonstrated. However, support for concurrent dual-po...
This presentation is about a 100 Gbit/s demonstrator project in its early stage. Our focus is to ... more This presentation is about a 100 Gbit/s demonstrator project in its early stage. Our focus is to present our project activities, and – at the oral presentation – highlight with a few examples from different subprojects. The project consists of activities in the following areas: high-speed electronics, assembly technology, optical components, and fibre-optical transmission. The project is a joint project with industry, where Optillion is the industrialand Chalmers is the academic partner. A corresponding project exists also at KTH, which focus on optical modulators.
The aim of this thesis is to describe some different ways in which non-perturbative methods enter... more The aim of this thesis is to describe some different ways in which non-perturbative methods enter in quantum field theory. In the thesis such methods enter in 1+1-dimensional theories: various Yang-Mills theories and electrodynamics. It also enters when treating charged bosons or fermions interacting with an external, classical field. In all these cases the interaction is treated exactly and we do not have to rely on perturbation theory. A good foundation for starting non-perturbative investigations in quantum field theory is a functional representation for the (canonical) algebra of the field operators. Such a representation is introduced and illustrated by various examples, mainly free fields and free fields coupled to external fields. The functional representation is well suited for a discussion of equilibrium quantum statistical mechanics by means of a density matrix. This is discussed in various examples. A non-equilibrium problem is also considered in the treatment of external...
2018 IEEE Custom Integrated Circuits Conference (CICC)
Directional communication at millimeter-wave (mmWave) frequencies is one of the key technologies ... more Directional communication at millimeter-wave (mmWave) frequencies is one of the key technologies under development towards the anticipated deployment of fifth generation mobile access (5G). Silicon-based multi-antenna systems are strong candidates for the implementation of such directional links; however, the performance requirements are in general significantly more challenging than those posed by mmWave WLAN links demonstrated so far (e.g. for 802.11ad). This work presents an overview of recent innovations in circuit design, antenna design, and beamforming architecture which enable complex phased arrays with precise and agile beamforming for mmWave-based 5G communications. Specifically, this work discusses: (1) a 28-GHz phase shifting transceiver front end, (2) beamforming architecture considerations to enable dual polarized operation as well as multi beam configurability, and (3) two different 28-GHz antenna-in-package (AiP) designs. These advances have been jointly demonstrated in a 64-element dual polarized phased array antenna module (PAAM) consisting of four SiGe ICs and an AiP array. The PAAM supports two simultaneous and independent 64-element beams in either TX or RX modes. PAAM-level measurement results over the air without calibration show +/− 50° beam scanning with >10dB silde-lobe rejection, <1.4° beam steering resolution with 0.6° RMS error, and 54 dBm saturated EIRP in each polarization. On-wafer measurement results from a front-end breakout and a full phased array IC are presented as well.
2017 IEEE International Solid-State Circuits Conference (ISSCC)
IEEE Transactions on Microwave Theory and Techniques
IEEE Journal of Solid-State Circuits
Dirac quantization of electrodynamics on a two-dimensional cylindrical space-time, is considered ... more Dirac quantization of electrodynamics on a two-dimensional cylindrical space-time, is considered in an explicit loop and functional representation. Expressions for a sufficient number of physical states are found, so that an inner product can be derived on the space of physical states. The relevant states are found to be a superposition of two disjoint sectors. The ground state is investigated and the investigations are met with partial success.
Eprint Arxiv Hep Th 9308015, Aug 5, 1993
We consider SU(N) Yang-Mills on a circle (cylindrical space-time) and quantize the eigenvalues of... more We consider SU(N) Yang-Mills on a circle (cylindrical space-time) and quantize the eigenvalues of the holonomy. In this way the Mandelstam identities associated with the holonomy are trivially solved. Furthermore we indicate that there are exactly two physically inequivalent representations of the algebra of gauge-invariant operators, resulting in different spectra.
2017 IEEE MTT-S International Microwave Symposium (IMS)
Classical and Quantum Gravity, 1994
We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associate... more We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associated algebra of gauge-invariant functions, the T-variables. We solve the Mandelstam identities both classically and quantum-mechanically by considering the T-variables as functions of the eigenvalues of the holonomy and their associated momenta. It is shown that there are two inequivalent representations of the quantum T-algebra. Then we compare this reduced phase space approach to Dirac quantization and find it to give essentially equivalent results. We proceed to define a loop representation in each of these two cases. One of these loop representations (for N = 2) is more or less equivalent to the usual loop representation.
Classical and Quantum Gravity, 1994
We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associate... more We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associated algebra of gauge-invariant functions, the T-variables. We solve the Mandelstam identities both classically and quantum-mechanically by considering the T-variables as functions of the eigenvalues of the holonomy and their associated momenta. It is shown that there are two inequivalent representations of the quantum T-algebra. Then we compare this reduced phase space approach to Dirac quantization and find it to give essentially equivalent results. We proceed to define a loop representation in each of these two cases. One of these loop representations (for N = 2) is more or less equivalent to the usual loop representation.
Optillion AB c/o …, 2003
This presentation is about a 100 Gbit/s demonstrator project in its early stage. Our focus is to ... more This presentation is about a 100 Gbit/s demonstrator project in its early stage. Our focus is to present our project activities, and -at the oral presentation -highlight with a few examples from different subprojects. The project consists of activities in the following areas: high-speed electronics, assembly technology, optical components, and fibre-optical transmission. The project is a joint project with industry, where Optillion is the industrial-and Chalmers is the academic partner. A corresponding project exists also at KTH, which focus on optical modulators.
Optillion AB c/o …, 2003
... Joakim Hallin2, Torgil Kjellberg2, Camilla Kärnfelt2, Bengt-Erik Olsson2, Magnus Andersson2, ... more ... Joakim Hallin2, Torgil Kjellberg2, Camilla Kärnfelt2, Bengt-Erik Olsson2, Magnus Andersson2, Herbert Zirath2, and Ulf Mattsson2,3 ... Concerning optical components, PIN photo diodes are available commercially with a bandwidth of 80 – 120 GHz (IPAG), but – to our knowledge ...
We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associate... more We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associated algebra of gauge-invariant functions, the T-variables. We solve the Mandelstam identities both classically and quantum-mechanically by considering the T-variables as functions of the eigenvalues of the holonomy and their associated momenta. It is shown that there are two inequivalent representations of the quantum T-algebra. Then we compare this reduced phase space approach to Dirac quantization and find it to give essentially equivalent results. We proceed to define a loop representation in each of these two cases. One of these loop representations (for N = 2) is more or less equivalent to the usual loop representation. 1
We report on advances in the OptCom-project within the fields of ultra high-speed electronics and... more We report on advances in the OptCom-project within the fields of ultra high-speed electronics and assembly technology. We highlight how we work towards our goal: a 100 Gbps transceiver demonstrator. Results of today include ICs from several generations of development. Our current best result is an IC operating at record-breaking 165 Gbps (serial bit stream). We will also outline our future activities towards more complex IC design, including electrical pseudo-random bit sequence generation and error detection at very high speed.
The kinematics of SL(2,R) Yang-Mills theory on a circle is considered, for reasons that are spell... more The kinematics of SL(2,R) Yang-Mills theory on a circle is considered, for reasons that are spelled out. The gauge transformations exhibit hyperbolic fixed points, and this results in a physical configuration space with a non-Hausdorff ”network” topology. The ambiguity encountered in canonical quantization is then much more pronounced than in the compact case, and can not be resolved through the kind of appeal made to group theory in that case. Email address: ingemar@vana.physto.se Email address: tfejh@fy.chalmers.se We have studied Yang-Mills theory on a cylindrical space-time, choosing the non-compact group SL(2,R) for our structure group. Since this undertaking may appear peculiar, we will begin by spelling out our motivation. First of all the Yang-Mills Hamiltonian is not positive definite whenever the structure group is non-compact. However, this is of no concern to us, since this operator will have nothing to do with the time-development of our model. Actually, we will not be ...
Next-generation mobile technology (5G) aims to provide an improved experience through higher data... more Next-generation mobile technology (5G) aims to provide an improved experience through higher data-rates, lower latency, and improved link robustness. Millimeter-wave phased arrays offer a path to support multiple users at high datarates using high-bandwidth directional links between the base station and mobile devices. To realize this vision, a phased-array-based pico-cell must support a large number of precisely controlled beams, yet be compact and power efficient. These system goals have significant mm-wave radio interface implications, including scalability of the RFIC+antenna-array solution, increase in the number of concurrent beams by supporting dual polarization, precise beam steering, and high output power without sacrificing TX power efficiency. Packaged Si-based phased arrays [1-3] with nonconcurrent dual-polarized TX and RX operation [2,3], concurrent dual-polarized RX operation [3] and multi-IC scaling [3,4] have been demonstrated. However, support for concurrent dual-po...
This presentation is about a 100 Gbit/s demonstrator project in its early stage. Our focus is to ... more This presentation is about a 100 Gbit/s demonstrator project in its early stage. Our focus is to present our project activities, and – at the oral presentation – highlight with a few examples from different subprojects. The project consists of activities in the following areas: high-speed electronics, assembly technology, optical components, and fibre-optical transmission. The project is a joint project with industry, where Optillion is the industrialand Chalmers is the academic partner. A corresponding project exists also at KTH, which focus on optical modulators.
The aim of this thesis is to describe some different ways in which non-perturbative methods enter... more The aim of this thesis is to describe some different ways in which non-perturbative methods enter in quantum field theory. In the thesis such methods enter in 1+1-dimensional theories: various Yang-Mills theories and electrodynamics. It also enters when treating charged bosons or fermions interacting with an external, classical field. In all these cases the interaction is treated exactly and we do not have to rely on perturbation theory. A good foundation for starting non-perturbative investigations in quantum field theory is a functional representation for the (canonical) algebra of the field operators. Such a representation is introduced and illustrated by various examples, mainly free fields and free fields coupled to external fields. The functional representation is well suited for a discussion of equilibrium quantum statistical mechanics by means of a density matrix. This is discussed in various examples. A non-equilibrium problem is also considered in the treatment of external...
2018 IEEE Custom Integrated Circuits Conference (CICC)
Directional communication at millimeter-wave (mmWave) frequencies is one of the key technologies ... more Directional communication at millimeter-wave (mmWave) frequencies is one of the key technologies under development towards the anticipated deployment of fifth generation mobile access (5G). Silicon-based multi-antenna systems are strong candidates for the implementation of such directional links; however, the performance requirements are in general significantly more challenging than those posed by mmWave WLAN links demonstrated so far (e.g. for 802.11ad). This work presents an overview of recent innovations in circuit design, antenna design, and beamforming architecture which enable complex phased arrays with precise and agile beamforming for mmWave-based 5G communications. Specifically, this work discusses: (1) a 28-GHz phase shifting transceiver front end, (2) beamforming architecture considerations to enable dual polarized operation as well as multi beam configurability, and (3) two different 28-GHz antenna-in-package (AiP) designs. These advances have been jointly demonstrated in a 64-element dual polarized phased array antenna module (PAAM) consisting of four SiGe ICs and an AiP array. The PAAM supports two simultaneous and independent 64-element beams in either TX or RX modes. PAAM-level measurement results over the air without calibration show +/− 50° beam scanning with >10dB silde-lobe rejection, <1.4° beam steering resolution with 0.6° RMS error, and 54 dBm saturated EIRP in each polarization. On-wafer measurement results from a front-end breakout and a full phased array IC are presented as well.
2017 IEEE International Solid-State Circuits Conference (ISSCC)
IEEE Transactions on Microwave Theory and Techniques
IEEE Journal of Solid-State Circuits
Dirac quantization of electrodynamics on a two-dimensional cylindrical space-time, is considered ... more Dirac quantization of electrodynamics on a two-dimensional cylindrical space-time, is considered in an explicit loop and functional representation. Expressions for a sufficient number of physical states are found, so that an inner product can be derived on the space of physical states. The relevant states are found to be a superposition of two disjoint sectors. The ground state is investigated and the investigations are met with partial success.
Eprint Arxiv Hep Th 9308015, Aug 5, 1993
We consider SU(N) Yang-Mills on a circle (cylindrical space-time) and quantize the eigenvalues of... more We consider SU(N) Yang-Mills on a circle (cylindrical space-time) and quantize the eigenvalues of the holonomy. In this way the Mandelstam identities associated with the holonomy are trivially solved. Furthermore we indicate that there are exactly two physically inequivalent representations of the algebra of gauge-invariant operators, resulting in different spectra.
2017 IEEE MTT-S International Microwave Symposium (IMS)
Classical and Quantum Gravity, 1994
We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associate... more We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associated algebra of gauge-invariant functions, the T-variables. We solve the Mandelstam identities both classically and quantum-mechanically by considering the T-variables as functions of the eigenvalues of the holonomy and their associated momenta. It is shown that there are two inequivalent representations of the quantum T-algebra. Then we compare this reduced phase space approach to Dirac quantization and find it to give essentially equivalent results. We proceed to define a loop representation in each of these two cases. One of these loop representations (for N = 2) is more or less equivalent to the usual loop representation.
Classical and Quantum Gravity, 1994
We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associate... more We consider the phase-space of Yang-Mills on a cylindrical space-time (S 1 × R) and the associated algebra of gauge-invariant functions, the T-variables. We solve the Mandelstam identities both classically and quantum-mechanically by considering the T-variables as functions of the eigenvalues of the holonomy and their associated momenta. It is shown that there are two inequivalent representations of the quantum T-algebra. Then we compare this reduced phase space approach to Dirac quantization and find it to give essentially equivalent results. We proceed to define a loop representation in each of these two cases. One of these loop representations (for N = 2) is more or less equivalent to the usual loop representation.
Optillion AB c/o …, 2003
This presentation is about a 100 Gbit/s demonstrator project in its early stage. Our focus is to ... more This presentation is about a 100 Gbit/s demonstrator project in its early stage. Our focus is to present our project activities, and -at the oral presentation -highlight with a few examples from different subprojects. The project consists of activities in the following areas: high-speed electronics, assembly technology, optical components, and fibre-optical transmission. The project is a joint project with industry, where Optillion is the industrial-and Chalmers is the academic partner. A corresponding project exists also at KTH, which focus on optical modulators.